Crispy Potato Skin with Dublin Bay Prawns and Irish Smoked Salmon

Crispy potato skin, filled with spinach, Dublin Bay prawns, Irish smoked salmon and glazed with Hollandaise sauce.

This recipe is a nice and simple starter, that I was use to serve in the restaurant. I have to say, it was a the customer's favourite. So, this is how it goes:

Ingredients for 4 people:

  • 4 medium size, rooster potatoes.
  • 12 large Dublin Bay prawns.
  • 4 tomatoes.
  • 200g cooked and pressed spinach.
  • 50g Irish smoked salmon.
  • 1/2 pt double cream.
  • Coarse sea salt.
  • Salt and cayenne pepper.

Pre-heat the oven at 200 degrees Centigrade. Wash the potatoes, roll them in the sea salt and place them on a roasting tray. Cook the potatoes for 50 minutes.

In the mean time, shred the smoked salmon. Peel and core the tomatoes. Cut them in 4 pieces. Shell the prawns and set them aside.

Take the cooked potatoes, trim each end and half them (in their width). Take the pulp of potatoes out to obtain nice tube shaped potato skins. Then put them in the oven at 120 degrees centigrade for another 40 minutes (until crispy).

In a pot, bring the cream to the boil. Add the spinach, Dublin Bay prawns and the smoked salmon. Cook gently for 10 to 15 minutes. Check the seasoning.

Place the potato skins on an oven tray. Fill them up with some spinach, 3 prawns per person, and some smoked salmon. Reduce the cream sauce a little bit and pour some of it in the skins. Place a couple of tomato petals on the top of the skins. Coat them with a soup spoon of hollandaise sauce and put under the grill for about 5 minutes.

Take 4 plates, place two potato skins in the center. Put a bit of Hollandaise sauce around them. Finish with a couple of sprigs of chives and the cooked prawn head against the potato skins.

Everything I eat has been proved by some doctor or other to be a deadly poison, and everything I don't eat has been proved to be indispensable for life. But I go marching on.
George Bernard Shaw

Gluten free.


Sauce: The principles of sauce consistency

In this third article about sauces, I will look at the physical structure of a sauce: its consistency.

As I wrote in my last post, a sauce is made of two basic things: flavour and texture. A great sauce is the perfect balance between the two.

When it comes to consistency, several problems can arise, when making a sauce, that can make it unusable. It can congeal, curdle or separate, making your sauce either unpleasant to look at or feel in the mouth.
Lets do a bit of chemistry. A sauce is mainly made of water, even cream ones. The only exceptions are butters and some vinaigrettes. The water or the fat in a sauce is defined by physicists as a continuous phase. It means that water is the material that bathe all the other components in the sauce. All these other components that swim in that continuous phase are called dispersed phase.
So, giving a sauce some consistency is making that water based continuous phase feel less watery by adding a non-watery, dispersed phase into it. By doing that the free movement of the water molecules is obstructed, making the sauce feel thicker.
To explain what is going on when we thicken a sauce, lets imagine a pot full of individual water molecules, H2O. Left on their on, these water molecules have plenty of space to run around: they are very mobile. The water is runny and can flow easily. Now, lets add some flour (long chains of tangled molecules), some oil (droplets), tomato paste (particles) or some bubbles (air) into it. Give it a good stir. Bizarrely, our water seems less watery. The molecules in the dispersed phase that we added into the water are, now, taking some space in our pot. Our molecules of H2O have less space to run freely: we have reduced their mobility. Our liquid thickens.
On a more poetic note, now. Depending on the thickening agent used, not only its consistency will vary, but its texture too. Fat (droplets) make the sauce feel creamier, air (bubbles) make it seem, some what lighter, flour (molecules) will make it sticky or slimy, fruit purée (particles) will make it smooth, etc.
As you may have already noticed, there are 4 kinds of thickening agents: Particles, molecules, droplets and bubbles. Lets see how they interfere with our continuous phase.
Thickening with particles consists of obstructing the continuous phase (water) with tiny bits of meat, vegetables, fruits, spices or seeds. It is what happens when making a tomato sauce or a salsa for example. When these foods are pulverized in the continuous phase all the cell walls and solid cells are broken apart and put in suspension in the water. Then, they obstruct and bind the water molecules, thickening the sauce. Such a mixture is called a suspension.
Depending on the size of the particles the sauce consistency will vary and its texture will be more or less smooth.
Note that suspensions have a tendency to settle and separate. Chefs will either increase the amount of dispersed phase by adding starch or reduce the continuous phase by straining the excess water.
Thickening with molecules consists of dispersing single types of molecules, such as starch, gelatin, pectin in the continuous phase. Starch, pectin and gelatin molecules are like long tangled chains of smaller molecules. When dispersed in water, they spread their long chains away taking more space. In result, the water molecules are obstructed. Then the sauce thickens. If the sauce is left to cool down, undisturbed, these molecules can bond with each other and form a loose network that trap the liquid, immobilizing it. It is called: gelation process. Such a mixture is called a gel. If you make a béchamel and let it cool down without stirring it. It will form a semi-solid mass when totally cold.
These types of thickened sauce are more stable that suspensions. They don't tend to separate as easily.

Thickening with droplets is what happens when you do a vinaigrette. This is how it works. Has you all know water and oil don't really like each other, they do not mix. But if you whisk hard enough, the large droplets of oil that you can see floating away in the water are broken into tiny little ones that block the movement of the water. Such a mixture is called a emulsion.
If you want to make a mayonnaise, for example you will require a third ingredient to stabilize the whole structure of your sauce. Such ingredients are called emulsifiers. These types of molecules have the property to attach themselves to water molecules on one end and to capture molecules of fat on the other end. The lecithin in the egg yolks of your mayonnaise are such molecules.
Thickening with bubbles, in substance adding consistency with air. Very peculiar indeed. But this is what happen in the head of a beer or the foam on the top of a good espresso. If you scoop a bit of the head of a pint of Guinness, for example, it can hold its shape. In a fluid, air bubbles behave, more or less, like solid particles. They disrupt the continuous phase that is water and obstruct its flow from one place to another. Such a mixture is called a foam.
The major disadvantage of such sauces is that they don't support gravity to well. They are fragile and evanescent. To delay the collapsing of such a structure, chefs thicken the liquid phase with substantial molecules or particles. It is the basic principle used to make a soufflé.

In general, most sauces that chefs make, are combinations of thickening agents. Very few sauces are simple suspensions or foams.


Sauces: Flavour

A sauce is concentrated flavour, in a liquid or semi-liquid form that complement or enhance the flavour of the main ingredient of a dish. So, a sauce is made of two distinct parts that are the flavour and the consistency. Lets put the complex subject of sauce textures to the side, for the moment, and have a closer look at the vast world of flavours.

Flavour is the combination of two sensations: taste and smell (aroma).

Taste is perceived on the tongue. There are five basic sensations related to taste: saltiness, sourness, savouriness, sweetness and bitterness. These sensations are triggered by water-soluble chemicals, salt, sugars, sour acids, savoury amino-acids and bitter alkaloids. The "hot" pungency and astringent sensations are not true tastes they are classified as a form of pain. But still perceived by our tongue.

Smell is perceived in the upper nasal region and comes in thousands of different aromas. They usually are described by the foods they remind us of. They have been classified in 25 different genres (groups). They are: floral, spicy, citrus, berry, tree fruit, tropical fruit, non-vinifera grapes, dried fruit, artificial fruit, green leafy, green stemy, dried leaves, nutty, phenolic, caramel, burnt, papery, hot, sulfur, yeasty, bacterial, moldy, earthy, oxidized, and contaminated (source Cornel University).
The molecules that we can smell are usually more soluble in fat than in water. That little part of them that aren't embeded in fats are the one that we can smell. Being water-soluble, these molecules can escape more easily into the air where our smell detectors can catch them.

So, when we are making a sauce we have to make sure that the combination of taste and aroma is respected. Neither of the two sensations alone is fully satisfying. But it is not all, recent studies have demonstrated how taste sensations affect our smell sensations. They showed that the sugar in sweet food enhances our perception of aromas. It is also true with salt in savoury foods.

Sauces as carrier of flavours form a broad spectrum. At one end they can be made of a simple mixture that bring a pleasing contrast to the main ingredient itself or add a flavour that is missing. Butter or cream provides richness to mash potatoes, salsas add pungency to fish or chicken. At the other end of the spectrum are complex flavour mixtures that fill your mouth and nose with sensations. These sauces provide a strong environment in which the flavour of the main ingredient blends itself. Amongst those, the "jus" of the classic French tradition. Their complexity comes from the extraction and concentration of savoury amino-acids and other taste molecules as well as the generation of meaty aromas by mean of browning reactions (maillard reaction) between amino-acids and sugar. In the Chinese tradition, braising liquids based on soy sauce get their complexity from the cooking and fermentation of soybeans. In Indian, Thai and Mexican cooking the complex flavours come from spice blends made of a half dozen or more, strongly aromatic and pungent ingredients.

In the light of all what we know, now, about flavour, taste and aromas lets tackle the main problem that all chefs come across: how to improve a sauce. There are two basic principles that can help to analyze and improve a sauce.
  • The first one is to look at a sauce as an accompaniment of the main ingredient in the recipe and understand that it is going to be eaten in a much smaller quantity. Therefore a sauce should have a concentrated flavour. Just keep in mind that if a spoonful of your sauce taste too strong, it should be just right on a piece of meat or some pastas. You should also remember that thickening agents can reduce the flavour of your sauce. So, it's important to taste and adjust the flavour of your sauce after thickening.
  • The second one is to look at your sauce not as a chef but as a chemist. A satisfying sauce stimulates more or less all of our chemical receptors. You know that feeling: "it doesn't taste quite right, something is missing!" It is probably the problem, it is missing in one or more of the chemicals that activates our sensations. The trick here, is to try to rectify the amount of saltiness, acidity, sweetness, sourness, bitterness or savouriness by little touches keeping in mind the overall balance of the sauce.

It seems easier said than done, don't worry there is nothing that a bit of practice can't overcome. Even top chefs need to practice.



In my next few articles, I will be looking at what makes the difference between a good cook and a not so good one: sauces. Hundreds of thousands of them exist; they represent the gastronomic culture of a continent, of a country. Henry Babinsky, French mining engineer and writer of "gastromie pratique" defined sauces as a flavourful liquid of various consistency that enhance the main ingredient of a dish. August Escoffier, define the making of sauces as an art, and emphasize about the importance of getting the texture of a sauce right. So, as the precepts of these two, one a famous "gastronome" , the other a famous chef always pointed at the word: texture. So, I decided to focus my research about sauces, on the science of thickening, the influence of texture on flavour, the importance of salt, the different thickening agents and how they work. These subjects are going to be at the centre of my next few posts. But, first of all, let's have a closer look at what a sauce is and how they have evolved through history.

The Oxford dictionary of English defines a sauce as a liquid or semi-liquid substance served with food to add moistness and flavour.

The Larousse Gastronomic definition of a sauce is a form of seasoning, more or less liquid which complements or is used to cook a dish.

So, if I got it right a sauce is a concentrate of flavour in a liquid or semi-liquid form that complements a dish. The word sauce comes from the Latin word salsus which means salted. No surprise, there, as salt has been, since the beginning of time, the main source of seasoning in cooking (not to mention salt has been the only means of preservation of food). We are even born with some nerve endings at the tip of our tongue that are especially designed to taste salt.

Europe is only one of the parts of the world that have evolved sauces with large appeal in modern times. Nowadays, many sauces are popular far from their region of origin: Chinese soy-based sauces, thick and spiced Indian sauces, fiery Mexican salsas and chilli-thickened moles. But it was on the old continent more precisely in France that generations of chefs developed and codified sauces to what became a systematic art and an international standard.

Our first knowledge of a sauce-type of preparation comes from the Romans. A Latin poem from 25 BC, Moretum, describes a peasant farmer making a spread of pounded herbs, cheese, olive oil and vinegar, an ancestor of Pesto, that gave a pungent, salty, aromatic savour to his flatbread. A few centuries later, the Latin cook book, De Re Coquinaria, attributed to Apicius makes it clear that sauces played a major role in the dining of the Roman elite. A quarter of the recipes in this book (more than 500) are sauces recipes. It is in this book, also, that the word ius the ancestor of juice or the French jus appears for the first time. Apicius also sets the thickening precepts that are still in use to thickened our modern sauces.: vegetable and fruit purees, nuts, egg yolks - both raw and cooked, bread even pure starch. Flavouring was provided by about half a dozen herbs and spices, vinegar and honey are common ingredients too. Saltiness and savouriness were supplied by a type of fermented fish: the Garum.

Between Apicius time and the Middle Ages not much is known about cooking. The oldest cooking manuscripts that survived were dated from the 14th century. They describe major changes in the techniques used to prepare sauces. Medieval sauces tend to use many spices. They were thickened with bread and vegetable purees, but meat started to be used as a thickening agent. Pure starch was no longer in use, cream and butter still weren't. If the texture agents haven't change much since the ancient time, the flavouring agents have. Fish sauce disappeared and was replaced by vinegar and unripe grape juice: verjus. Thanks to the discovery of new worlds in the East and the Middle-East new spices made their ways into European sauces: cinnamon, ginger or grain of paradise. The introduction of almonds from the Middle-East made it the main nut used as a thickening agent.

The Middle Ages is the starting point of the era of the stock - meat or fish - as the main flavouring agent. By using stocks, chefs have discovered the technique of thickening sauces by concentration, as a result they discovered that gelatin could be a peculiar but quite efficient thickening agent. It is the beginning of the savoury jellies, aspics.

The 15th century, brought another evolution in the use of stock. Chefs started to perfect their techniques of stock clarification: it was the birth of consommés. This century saw changes in the terminology of sauces too. The words sauce, coulis, soup, salsa, gravy, Jus or bouillon started to appear on cookery manuscripts.

It was in three centuries between 1400 and 1700, that the sauces of our time found their roots. Recipes of those time, call for fewer spices. Vinegar and verjus gave their place to lemon juice. The use of bread and almonds as thickening agents were replace by flour, butter and egg emulsions.

Around 1750, Chef Francois Marin incorporated his knowledge of the Chinese flavour harmony concept into his own cooking. Both Marin and a chef I Yin from ancient China, spoke of balance and harmony. I Yin would bind together sour, sweet, bitter, salty and pungent ingredients while the French chef pots would contain meat juices which would generate complexity and harmony. Francois Marin introduced the concept of the sauce as a complement that deepens and integrates the flavour of the main ingredient with the rest of the other dish. The preparation of sauce in those times required a huge amount of flesh that would not appear in the final dish. With Marin started the glorious time of rich bouillons, stocks, consommés, jus and "restaurants" that will last until the years of the "Nouvelle Cuisine" and "Fusion Cooking".

In 1789, came the French revolution, and with it came the diminishment in the standards of kitchens of the French great houses as less wealth meant less staff. It is then that the first fine restaurants appeared, opened by the former chefs of the bourgeois households. The impact of the French revolution was assessed by Chef Antonin Careme (1784-1833) in his book "Preliminary Discourse" to his Maitre d'hotel francais. Careme made a summary of the old, costly traditional cooking. His input to in the progression of cooking and sauce making was to organize and simplify and classify what Marin foresaw.

About 200 years later, French Chef August Escoffier (1846-1935) in its Guide Culinaire attributed the eminence of French cuisine in the rest of the world directly to its sauces. In the hands of Careme and Escoffier the new way of thinking that came out of Marin's kitchen, became Classic French cooking and the cornerstone of fine dining throughout the western world. But for 40 years, Chefs just kept going in round in circles in the rigid classic cooking system. They just kept on reproducing over and over the same recipe.

In the 1960's came Nouvelle Cuisine, led by Paul Bocuse, Alain Chapel, Michel Guérard and the Troisgros Family and later on, Joel Robuchon. This new concept allow chefs' imaginations to flourish and asserted the virtues of freshness, economy and simplicity. The main aspect of the Nouvelle Cuisine was that the food was to served intact instead of the old ways of the food's total dissection. With the Nouvelle Cuisine came a more rational use of the sauce Espagnole that was the cornerstone of Escoffier's era. Lighter sauces, now had a place in cooking, the use of flour and butter thickening agents were to be replaced by light emulsions, dressings, flavoured oils and cooked vegetable or fruits purée.

Nowadays, Escoffier's Guide Culinaire is considered by most chefs as the cooking "Old Testament". Chefs around the world, including myself, consider Le Grand Livre de Cuisine by French Chef named Alain Ducasse as the cooking "New Testament". His cooking represents the next step in the evolution of cooking and sauce making. He has been able to refine even more the old precepts and integrate, flavours from the global village we leave in as well as the new dietary needs of our modern world. I think that he has reached what Francois Marin and I Yin were striving for, many centuries ago: subtleness and delicacy, balance and harmony.

But, it is history in the making, so it is up to you to find who is going to write the next chapter in the history of sauces.