Baked Beans & Ground Beef Casserole

Baked Beans & Ground Beef Casserole
Ingredients
1 lb ground beef
1 medium yellow onion, diced
1 medium green bell pepper, diced
1 cup ketchup
1 tsp mustard
1/2 cup brown sugar, packed
2 tsp Worcestershire sauce
2 (15 oz) cans pork and beans (do not drain)
salt & black pepper, to taste
1 TBS butter
Instructions