Start by cooking the bacon using your preferred method. You can bake it in the oven for even crispiness or fry it in a skillet over medium heat. Once the bacon is crispy, transfer it to a paper towel-lined plate to drain excess grease. After it cools, cut it into 1-inch pieces and set aside for later.

While the bacon is cooking, finely chop the red onion and red bell pepper, and mince the garlic. In a very large pan or stock pot set over medium-high heat, add the ground beef, chopped onion, chopped bell pepper, and minced garlic. Season lightly with salt and black pepper. Cook the mixture, breaking up the beef with a spoon, until the beef is completely browned and no pink remains, and the vegetables are tender. Drain any excess fat from the pan, then return the beef mixture to the pot.

Add the rinsed and drained mixed beans to the cooked beef mixture in the pot. Pour in the tomato ketchup, barbecue sauce, packed dark brown sugar, whole grain mustard, soy sauce, and Worcestershire sauce. Stir everything thoroughly to combine. Let the mixture simmer on medium-low heat for about 5 minutes to meld the flavors together. I sometimes like to taste and adjust the balance of sweet and tangy to my liking by adding a little extra barbecue sauce or mustard.

Preheat your oven to 350° F. Lightly spray a 9×13-inch baking dish with cooking spray. Pour the hot baked beans with hamburger mixture from Step 3 into the prepared casserole dish and spread into an even layer.

Sprinkle the cooked and chopped bacon from Step 1 evenly over the top of the casserole. Cover the dish with aluminum foil and bake in the preheated oven for 40-45 minutes. Remove the foil and continue baking for another 10 minutes so the top gets nicely browned and bubbly. Let the dish rest for about 10 minutes before serving to help the flavors settle. I find that letting it sit briefly makes it easier to serve and even tastier.