In a large skillet over medium heat, cook the bacon and onion until the bacon is cooked through and starting to crisp and the onions are translucent, 5-7 minutes. Drain excess grease.
Rinse and drain only two cans of the beans. Add the rinsed and drained beans to the skillet along with the two cans of undrained beans.
Stir in the ketchup, brown sugar, molasses, vinegar, Worcestershire sauce, mustard, garlic powder, salt, pepper, and paprika.
Oven Directions: Preheat the oven to 350 degrees F. Transfer the baked beans to an oven-safe 9X13-inch dish and cover with foil. Bake for 1 hour. Uncover and bake for 15-20 more minutes until bubbling. Remove from the oven and let sit for 15 minutes. They'll thicken up more as they cool slightly. Season to taste with additional salt and pepper, if needed.
Slow Cooker Directions: Tansfer the beans to the insert of a 6-quart or larger slow cooker. Cook on low for 6-8 hours or on high for 3-4 hours until bubbling and slightly thickened. They'll thicken up more as they cool slightly. Season to taste with additional salt and pepper, if needed.
Notes
Brown Sugar: with the 1/3 cup brown sugar, these are mildly sweet. If you'd like them sweeter, increase the brown sugar to taste.