This will make more filling than you will probably need, but if the egg ratio is much higher than this recipe, the filling will not be as creamy
1½ cup whole-milk ricotta (preferably small batch production)
¼ cup finely grated Parmesan Reggiano Cheese
Salt and Pepper to taste
A sprinkle of grated nutmeg (optional – only if you prefer)
1 egg lightly whisked
Stir the first four ingredients together in a bowl with a spoon or spatula. Taste and adjust the seasonings. Whisk the egg separately in another bowl, and then stir into the cheese mixture.