Tagliatelle with Four Cheeses

Here is a dish which, by its very nature, is ideally suited for experimentation. Essentially its sauce is composed of 4 cheeses. The recipe I list below is the classic, but you can combine any cheeses you like. Just follow your instinct. I find, for example, that veined cheeses are not successful in this dish. Although single portions can easily be made by halving the ingredients, I am providng a recipe for 2 servings since I like this recipe for gastronomic tête-à-têtes.