Preheat oven to 350 degrees.
Cut bacon slices into small pieces. Add to a skillet and cook until bacon is crispy. Place bacon on a paper towel and drain all but about 2 tablespoons of bacon grease from the skillet.
8 slices bacon
Place ground beef in the skillet and season with salt & pepper. Break apart and brown over medium high heat. Add chopped onion and continue cooking until beef is no longer pink and onions are translucent, about 3-5 minutes.
1 # ground beef, 1 tsp. salt, 1/2 tsp. black pepper, 1/2 cup yellow onion
In a large mixing bowl add undrained pork & beans, drained kidney beans and drained butter beans. Add hamburger mixture and bacon.
2 - 16 oz. cans pork & beans, 1 - 16 oz. can kidney beans, 1 - 16 oz. can butter beans
In a small bowl combine ketchup, mustard, brown sugar, molasses, vinegar & Worcestershire sauce. Mix well and combine with beans.
1/2 cup ketchup, 1 tbsp. yellow mustard, 1/2 cup brown sugar, 2 tsp. molasses, 1 tbsp. apple cider vinegar, 1 tsp. Worcestershire sauce
Pour into a 9X13 baking dish. Bake uncovered for 1 hour. Remove from oven and let sit for 10 minutes for sauce to thicken before serving.