I lifted this recipe from this book of Mildred's, but I adapted it to suit, so I figured pairing myself with Jack in the title wasn't dishonest.
1 lb. bacon, cooked crisp, crumbled, and set aside
a few tablespoons of bacon grease, reserved
1 lb. ground beef
one onion, chopped
4-6 cans of beans (I used two undrained cans of pork and beans, a can of drained/rinsed kidney beans, and a can of drained/rinsed white beans-- pinto, I think)
1 and 1/2 tsp. dried mustard, or to taste
additional prepared mustard, to taste, if desired
1/2 cup ketchup, or to taste
1 tablespoon apple cider vinegar, or to taste
1 tsp. salt
3/4 cup brown sugar
a smidge of blackstrap molasses, if desired
Cook the ground beef and onions until beef is cooked and onions are translucent. Drain off the fat. Combine beef and bacon with remaining ingredients, including the deliciously greasy bacon grease, to taste. Spoon into a greased baking dish and bake, uncovered at 300 degrees, for 1 hour or until beans reach desired thickness OR put in crockpot on low. Simmer all day until supper. I usually stir in the bacon pieces when the beans have already cooked for a bit so that the bacon doesn't become limp and soggy.
I tasted this a few times while preparing, and though I can't remember for sure, I think I added a bit more vinegar and I think I also sprinkled in a tad of garlic powder.