In a large skillet, cook bacon until just crispy.
Remove strips to drain on a paper towel.
Using 2 tablespoons of reserved bacon grease, saute diced onion over medium high heat until translucent.
In a large bowl combine two cans of baked beans, diced onions and crumbled up bacon.
Stir in ketchup, mustard, brown sugar, pepper and salt.
Preheat oven to 375 degrees.
Pour beans into a 9x13 baking dish and cover with foil.
Bake for 20 minutes, remove foil and bake for another 10 minutes or until bubbly around the edges.
Let cool for 5 minutes before serving.