In a large bowl, beat the egg and stir in tomatoes, onion, parsley, oats, Parmesan cheese, salt, and pepper. Then mix in by hand the Italian sausage and ground turkey just until blended.
Make into a large meat loaf on a baking sheet (like a jelly roll pan), patting to remove any air spaces. Bake for one hour. Top with spaghetti sauce and continue baking 15-30 minutes. Let stand 10 minutes before serving.
Serving Suggestions: Pasta, steamed broccoli, and baked butternut squash.