Line pan with dough, prick holes to allow steam to escape, sprinkle with a little flour.
Remove casing from sausage, cut into pieces, brown with 2 tablespoons of water until cooked.
Combine ricotta and mozzarella. Add sugar and eggs one at a time, beating after each addition with wooden spoon.
Add cooked sausage, prosciutto, parsley, grated Parmesan. Blend well.
Pour into pan with bottom crust. Cover with top crust.
Bake at 400º for 15 minutes then 325º for 40 - 45 minutes. Let stand 5 minutes before serving.