Step 1: In a large skillet, cook the diced bacon over medium heat until crispy. Remove bacon with a slotted spoon to a paper towel-lined plate. Reserve about 2 tablespoons of bacon fat in the skillet.
Step 2: Add chopped onion and bell pepper to the reserved bacon fat in the skillet. Sauté over medium heat for 5-7 minutes, until softened. Stir in minced garlic and cook for an additional minute until fragrant.
Step 3: Thoroughly rinse and drain the canned great northern or cannellini beans under cold water.
Step 4: In the bowl of your crockpot, combine the rinsed beans, sautéed onion and bell pepper mixture, crispy crumbled bacon, ketchup, molasses, brown sugar, Dijon mustard, apple cider vinegar, Worcestershire sauce, and liquid smoke.
Step 5: Stir all ingredients together until well combined and the beans are evenly coated with the sauce.
Step 6: Cover the crockpot and cook on low for 8-10 hours, or on high for 4-6 hours, until the beans are tender and the sauce has thickened to your desired consistency.
Step 7: About 30 minutes before serving, stir the beans. Taste and adjust seasonings as needed, adding more salt, pepper, or brown sugar if desired. If the sauce is too thick, add a splash of water or broth; if too thin, remove the lid for the last 30-60 minutes of cooking.