1/4 c. butter or shortening
2 c. chopped onions
1 to 1 1/2 lb. ground beef
1 tsp. salt
2 tbsp. mustard
2 tsp. vinegar
2 (1 lb.) cans pork and beans
1 (1 lb.) can kidney beans
1/4 c. brown sugar

Heat shortening or butter in a skillet. Add onions and simmer until yellow. Add ground beef and brown slightly. Add remaining ingredients, then pour in baking dish.

Bake at 400°F for 30 to 40 minutes.