Creamy Beef Stroganoff

1-1/2 lbs. stew beef, cubed
1 onion, sliced
2 10-3/4 oz. cans cream of mushroom soup
2 T. catsup
2 t. WSorcestershire sauce
1 t. pepper
1 to 2 c. sour cream
12-oz pkg. medium egg noodles, cooked

Place beef and onion in a slow cooker; set aside. Combine soup, catsup, worcestershire sauce and pepper; stir into beef mixture. Cover and cook on low setting for 8 to 10 hours. Stir in sour cream and heat through. Spoon over prepared noodles to serve.