A pasta made from solely egg yolks, without any flour or other ingredients? It’s possible, thanks to marinated egg. It’s a technique that renders the yolk solid enough to handle, to either roll it out into sheet pasta or to shape it at will.
As many of us already know, marinating an egg yolk is very simple: mix an equal amount of sugar and coarse salt (for 3 yolks you’ll need around 250 g of both), and spread half of the sugar/salt mixture in a container. Then create small holes, placing the yolks on top of them, saving the whites for later use. Afterwards, carefully pour the rest of the mixture on top of the yolks and then wait. How long? For hen’s eggs, about 5 hours. But the longer we wait the thicker the consistency of the yolks will be. We can even get them hard enough to grate over pasta instead of cheese. Once we remove the yolks from the mixture, we only need to rinse them and dry them.
This procedure is a perfect application of denaturization, even though here it’s done “cold” (temperature isn’t always important). Salt and sugar, with their high hydroscopic powers, absorb all the moisture from the yolk, which is what denaturizes the protein. The longer the marination period, the less moisture in the yolk. Why salt and sugar? Salt on its own would be fine, but the taste of the yolk would be awful, so sugar is added to give it the right balance.