Step 1

Position an oven rack in the middle of the oven and preheat to 325 degrees F.

Step 2

Put the bacon in a large skillet and cook over medium heat, stirring occasionally, until crispy, 8 to 10 minutes. Remove the bacon with a slotted spoon to a paper-towel lined plate. Pour off all but 1 tablespoon of the bacon fat from the skillet. Add the onion and ground beef and cook, breaking up the beef, until the onion is softened and the beef is crumbled and fully cooked, about 5 minutes. If necessary, drain any excess moisture released from the meat. Add the cooked bacon, kidney beans, navy beans, pork and beans, ketchup, brown sugar, dry mustard, vinegar and salt. Stir together and then transfer to a 9-by-13-inch baking dish.

Step 3

Bake until bubbling and caramelized on top, 35 to 40 minutes.