Place 1/2 cup spaghetti sauce in the bottom of a 2-quart oblong casserole. Alternate layers of noodles, ricotta cheese (dropped by spoonsful), spaghetti sauce, Smoked Sausage and mozzarella cheese. Sprinkle top with oregano, Parmesan cheese and salt. Cover. Bake in a preheated 350 degree F oven 45 minutes until heated through.