To make this recipe gluten free, substitute the egg noodles with a certified gluten-free pasta that holds its shape well during baking. Also verify that the tomato sauce, Italian seasoning, cottage cheese, sour cream, and cheddar cheese are certified gluten free, as some packaged products may contain hidden gluten or anti-caking agents. If needed, slightly undercook the gluten-free pasta before assembling the casserole so it does not become overly soft during baking.