Layered Spaghetti

1 lb. ground chuck
1 large onion, chopped
1 jar (32 oz.) spaghetti sauce
1 pkg (8 oz.) thin spaghetti
1 carton (8 oz.) sour cream
1 tsp. oregano
1 cup sliced mushrooms
1 tsp. parsley flakes
1 cup shredded cheddar cheese
1 cup shredded mozzarella cheese
1/2 cup grated parmesan cheese

Preheat oven to 350 degrees. Sauté onions in 2 Tbl. cooking oil. Add ground beef & brown. Pour off excess grease and add spaghetti sauce and seasonings. Simmer 10-15 minutes to blend flavors. Cook spaghetti and drain. In a large casserole dish sprayed with non-stick spray, place 1/2 of the spaghetti, top with 1/2 of the sauce, evenly spread sour cream over sauce, top with mushrooms and sprinkle with 1/4 cup parmesan cheese. Repeat spaghetti and sauce mixture. Sprinkle with cheddar cheese, mozzarella and top with remaining 1/4 cup of parmesan cheese. Bake 30 minutes. Let stand 15 minutes before serving.

Changes - add some sweet Italian sausage, maybe some chopped pepperoni, add chopped bell peppers to the onions.