FRITTATA BATTER: Beat eggs, half and half, cornstarch, salt and nutmeg thoroughly until all ingredients are completely blended.
Blend the 2" spaghetti pieces, green onion rings and bacon pieces in a bowl until evenly mixed.
Coat a 1-1/2 qt round baking dish, including walls, with spray or margarine.
Empty the spaghetti mixture into the baking dish and spread evenly. Add the frittata batter to cover the filling mix.
Bake for about 25 minutes until center is set. When center is set, cover the frittata evenly with the Fontina and bake until cheese is golden. Turn off the heat and open oven door. Let the frittata sit in the open oven for 15 minutes for the batter to set more firmly and make removing from the dish easy. Before serving, sprinkle with Parmesan and cut into 4 wedges.