Last week, we learned to deal with the whole egg and the technique of separating the white from the yolk. In case you missed it, check out part 1 here. With that sorted, it’s time to deal with each component individually, starting with the yolk.
The yolk is fattier, and frankly, way more delicious than the white, which is why adding a few extra yolks to your crème brulee or flan mix or pasta dough makes for a richer end-product. It is often eaten raw, served atop a steak tartare or a bowl of Korean bibimbap. I once had a dish of mutton keema topped with a raw egg yolk, meant to be mixed into the dish before being picked up by pieces of warm buttery pav. The problem with raw egg yolk, though, is the high risk of salmonella. Using pasteurized eggs can help solve that problem.
Raw egg yolk is the secret ingredient behind one of the most beloved condiments all over the world: mayonnaise. Mayonnaise is basically an emulsion between two arch rivals: oil and water (in the form of vinegar or lemon juice). The reason this unlikely union occurs is because egg yolk contains a substance called lecithin, which holds on to both these things simultaneously, keeping them together. But because of the inherent enmity between the two main stars, it is very easy for a mayonnaise to split, especially when the oil is poured in too quickly while making it.
If you apply heat, the yolk tends to stabilize, creating a sturdier product. The best example for this is hollandaise, one of five mother sauces in French cuisine, the best friend of Eggs Benedict. It is made in a similar way to mayonnaise, except that melted butter is used instead of oil, and the entire mixture is whisked in a bowl placed over a water bath. The result is a sturdier sauce with more body to it. Using the same technique, but using sugar and other flavourings instead of fat and vinegar, you end up with a zabaglione or sabayon, a rich yet very light concoction that can be had as a dessert as it is along with some macerated berries, or used to make other more ambitious desserts, like the famous Italian tiramisu.
Another simple dessert element made with egg yolks is citrus curd, made by whisking egg yolks and sugar over heat like a zabaglione and adding the zest and juice of citrus like lemons, limes or oranges. It is famously used in the French Tarte au citron. You could also pipe it into eclairs or simply slather it on a warm piece of toast for a delicious snack.
Heat is not the only way you can cook a yolk, though. You could salt-cure it. Pack the yolks in a salt mixture for a few days and then dry them out in the oven to get a rubbery, intensely flavoured hockey-puck you can crumble over salads or pastas like carbonara. You could cure it in a mixture of soy sauce, mirin and aromatics like ginger to make a cured yolk with an Asian flavour.
Alright, moving on to egg whites. Devoid of its fatty partner, egg whites tend to be very nutritious and hence can be made into an omelette by weight-watchers. They are also pretty neutral in flavour, which is why in its raw form, egg whites are commonly used in cocktails. Adding egg whites to a cocktail makes it creamier and gives it a foamy cap. It enhances the texture of the drink without tampering with the flavours. Pasteurisation can once again solve the salmonella problem while dealing with raw egg whites.
Whip out a whisk, and the humble egg white is transformed into something magical. When whisked with sugar, the strands of protein in the egg white open up and interact with the sugar molecules to form a foam, making a meringue. It can be whisked into cakes to make them fluffy or into soufflés which helps them rise. Meringues form the base of desserts like pavlova, mousses and of course, the French macaron. A tiny amount of acid, in the form of vinegar or cream of tartar is added to stabilize the foam, making a French meringue. Another way of stabilizing the foam is by applying heat, either by whisking the eggs and sugar over a water bath to make a Swiss meringue, great for making buttercream fillings for cakes; or by adding hot sugar syrup to the whites instead of regular sugar to make an Italian meringue, ideal for sturdier foams used in marshmallows and nougat.
Let’s finish by looking at a dessert which brings together the two parts of the egg into a satisfying whole. A lemon meringue pie essentially has three components: the pastry shell, the lemon curd filling and the meringue topping which is then torched or baked in the oven for a few seconds to develop some colour and toasty flavor notes. The lemon curd filling, made using the yolks, lends it a voluptuous richness which is deftly cut through by the sharp tang of the citrus. It is rich, luscious and extremely moreish. Compare that with the meringue topping made with egg whites which is much sweeter, with subtle toasty and bitter notes from the torching. The texture is creamy, airy and vanishes in your mouth. Both of these components share a common origin, the egg. Now that’s what I call versatility.
We’ve moved from the simple boiled egg to some of the most intricate confections, and the egg lies at the heart of all of them. And I have barely scratched the surface here. There are few ingredients more versatile than the egg. Treat it with the respect it deserves.