In a skillet over medium heat, cook the sausage until evenly brown. Drain, and mix in the spinach and Alfredo sauce. Season with pepper. Continue cooking until spinach and sauce are heated through.
In a bowl, mix the Cheddar cheese, ricotta cheese, Parmesan cheese, and egg.
In a 9x13 inch baking dish, layer 1/3 of the sausage mixture, 1/3 of the noodles, and 1/3 of the cheese mixture. Repeat layers twice, and top with mozzarella cheese.
Cover, and bake 45 minutes in the preheated oven. Let stand 15 minutes before serving.
