To make this Million Dollar Lasagna gluten free, replace the regular lasagna noodles with certified gluten-free lasagna noodles. Verify that the Italian sausage or ground beef, spaghetti sauce, tomato sauce, Italian seasoning, cottage cheese, cream cheese, sour cream, mozzarella, Parmesan, and all packaged ingredients are labeled gluten free. Use clean cookware, utensils, and a clean baking dish to prevent cross-contact with gluten-containing ingredients.