Leftover Egg Yolks? Three Ways
Aioli, pasta, or custard, egg yolks are the more valuable leftover, and they only last two days.
- Preparation
- 15 min
- Cook/bake time
- 15 min
- Total
- 30 min
- Difficulty
- Medium
- Calories
Aioli, pasta, or custard, egg yolks are the more valuable leftover, and they only last two days. After making meringue, whipped egg whites, or an egg white omelet, you are left with egg yolks, and they are more delicate than egg whites. They dry out on the surface and do not freeze well. These three methods use them up quickly and rewardingly.
Why this works
An egg yolk is a natural emulsion of water, fat, and protein, held together by lecithin, a molecule with a water-loving end and a fat-loving end. This is why a single egg yolk can bind a quarter liter of oil, and it is the key to mayonnaise, aioli, and hollandaise sauce. Its second property is its coagulation temperature. Egg yolks set between 65 and 70 degrees, which is significantly earlier than egg whites and much earlier than most people expect. This is exactly why the pan for a carbonara is taken off the heat before the egg yolk is added. The residual heat of the pasta is enough to bind it into a sauce, whereas the hot pan would turn it into scrambled eggs within seconds.
Step-by-step instructions
- 1
Way 1: Build the aioli
Whisk the egg yolks, garlic, lemon juice, and salt in a tall container. Add the oil drop by drop at first and whisk continuously. The first fifty milliliters decide everything. As soon as the mixture is visibly lighter and thicker, you can continue pouring in a thin stream.
- 2
Way 2: Bind the pasta off the heat
Boil the spaghetti and reserve a cup of pasta water. Whisk the egg yolks, Pecorino, and plenty of pepper in a bowl. Add the drained pasta and stir immediately, adding hot pasta water by the spoonful until a creamy sauce forms. Do all of this outside the pan, as egg yolks set at 65 degrees.
- 3
Way 3: Cook the custard to the rose stage
Heat the milk and vanilla, whisk the egg yolks with sugar, and slowly pour in the hot milk while stirring. Return to the pot and stir over low heat until the custard coats the back of a spoon, which is around 82 degrees. A finger drawn through it must leave a clear path. Pour through a sieve immediately.
- 4
Store the remaining egg yolks
Whatever is left goes into a jar covered with a thin layer of water. This prevents the skin that otherwise forms within hours. They will keep for two days in the fridge, and you should carefully pour off the water before using them.
