The Best Baked Beans

This was my mother's baked bean recipe and I have never found one that I liked better than this one.
It is the best baked beans recipe ever.

Ingredients

12 slices bacon
2 medium onions
1 teaspoon garlic powder
1/2 teaspoon dry mustard powder
1/2 cup firmly packed brown sugar
1/3 cup cider vinegar
1/4 cup ketchup
1 (15.5 ounce) can kidney beans, drained and rinsed
1 (15 ounce can) butter beans, drained and rinsed
2 (16 ounce) cans baked beans

Instructions

Heat oven too 350 degrees.
Cook bacon until crisp. Drain on paper towel. Chop into small pieces.
Chop onions into small pieces and saute in bacon grease until tender and browned.
Combine onions and bacon with other ingredients in shallow casserole dish.
Bake uncovered for 60 - 70 minutes or until hot and bubbly.

Serves 6-8.