Cook bacon in skillet until crisp, then crumble and set aside.
Cook beef in skillet until no pink remains. Add onion, sauté just until tender.
Combine beef, onion, ketchup, salt, brown sugar, mustard and vinegar in a 3 qt baking dish or crock pot. Partially drain all the beans (I don’t drain the baked beans) and add to the baking dish or crock pot, stirring gently to mix. Sprinkle with bacon.
Bake at 350 F for 40 minutes or cook in crock pot until heated through.
For vegetarian version just sauté onion and add to bean mixture. If using dry tofu crumbles it isn’t necessary to rehydrate them first, I just stir them into the mixture. It may require addition of water to the mixture if it gets too thick, I just play it by ear. When using frozen crumbles or gimme lean ground “beef” I heat it up in the pan with the onion before adding to the bean mixture.