Cook sausage, onion and red pepper in large skillet over medium heat until meat is brown and crumbly; drain and cool. Combine Mozzarella cheese, Ricotta cheese, egg and sausage mixture; set aside.
Spray 13x9-inch baking dish with non-stick cooking spray. Trim phyllo sheets to 13x9 inches. Working with one sheet at a time (keep remaining phyllo covered), spray 8 sheets with cooking spray.
Place phyllo pastry into prepared baking dish. Spoon filling over phyllo. Spray remaining 8 sheets with cooking spray and layer over filling. Using a sharp knife, cut into 8 squares. Bake, uncovered, in preheated 400°F oven 35 minutes or until golden brown.