12 oz. mild Italian sausage
1 c. sliced onion
1/4 lb. sliced mushrooms
1 (15 1/2 oz.) jar Ragu plain
1/2 lb. spaghetti
1 tbsp. parsley
1/2 c. shredded Swiss cheese
1/3 c. Italian salad dressing

Or use homestyle and can leave out mushrooms above.

Brown sausage in onion with mushrooms; drain oil. Stir in Ragu sauce and simmer. Cook spaghetti and drain. Mix in parsley, Swiss cheese and salad dressing. Pour spaghetti mixture into a casserole dish. Next, pour sausage mixture on top and serve.