In skillet, cook sausage over medium-high heat for 3 minutes, chopping into small pieces. Add mushrooms, onion, and peppers. Cook and stir 5 minutes longer or until sausage is no longer pink and the vegetables are tender; drain well and set aside. In mixing bowl, beat cream cheese until smooth. Gradually beat in eggs and cream. Stir in cheeses, salt, pepper, nutmeg, and sausage mixture. Pour into baked pastry shell. Bake, uncovered, at 350 degrees for 40 to 45 minutes or until a knife inserted near center comes out clean. If necessary, cover edges of crust with foil to prevent over-browning. Let stand 10 minutes before serving. Makes 8 servings.