Combine the following ingredients: 1 pound bleached flour, 2 ounces sweet butter, 5 eggs, and 1 pinch salt. Work the dough long enough to allow the butter to be incorporated inside the dough. Wrap the dough in a towel and let it rest, for at least one hour, inside the refrigerator.The Filling-- For the filling, steam the spinach and chop it very fine. In a bowl, beat together 2 eggs with 7 ounces freshly grated Parmesan cheese, 1 pinch each: salt, black pepper, and nutmeg. Add 15 ounces dry ricotta cheese and mix very well, but not too long. If you mix it too much, the mixture will become liquid.The Agnolotti-- Roll out the dough in a thin layer and brush it with an egg wash (made from 1 egg). With the help of a teaspoon to make a "walnut" shape, place the spoon on the dough and cover it with another layer. Cut with a round pasta cutter 2 inches in diameter.
Stuff the pasta with the filling and cook in boiling water until the agnolotti come to the surface of the boiling water. For the sauce, bring 1 quart heavy cream to a slow boil and add 4 ounces sweet butter, 6 ounces freshly grated Parmesan cheese, 4 ounces mascarpone cheese, 1 pinch of salt, 1 pinch of nutmeg, 2 pinches white pepper. Boil slowly for five minutes, constantly stirring with a wooden spoon. Serve agnolotti on warm plates with warm sauce.