Remove casings from sausage. Brown sausage and ground beef in large skillet, about 6 minutes or until no longer pink, stirring to break up pieces. Drain fat. Stir 1/4 cup Parmesan into sausage mixture.
Heat oven to 350°F.
Combine ricotta, egg, parsley, nutmeg and remaining 1/4 cup Parmesan in small bowl until blended.
Drain spinach well. Press between pieces of paper toweling to remove all excess moisture.
Spoon one-quarter of marinara sauce over bottom of 12 x 9-inch baking dish. Arrange 3 noodles over sauce. Spoon one-third ricotta mixture over noodles. Sprinkle with one-third meat mixture and one-third chopped spinach. Top with one-quarter marinara sauce and one-quarter mozzarella. Repeat two more times, starting with noodles. Top with the last layer of noodles, remaining sauce and remaining mozzarella. Cover with aluminum foil.
Bake in 350°F oven 30 minutes. Remove foil. Bake another 10 to 15 minutes or until lightly golden and bubbly. Let stand for 10 minutes before serving.
