In a well greased 9 x 13 inch pan put 1/2 package wide egg noodles (uncooked).

In large bowl combine the following:

1 lb. raw LEAN ground beef, torn in sm. pieces
1 tbsp. instant diced onion
1 lg. jar Prego sauce with mushrooms
1 c. water
1 tsp. oregano

Mix and pour over uncooked noodles. On top lay two 8 ounce packages Mozzarella cheese. Cover and bake 45 minutes at 350 degrees. Uncover and bake 10 minutes more. Let stand 5 minutes before cutting.