Preheat your oven to 350°F (175°C).
Transfer the pork and beans into an oven-safe baking dish. Incorporate the brown sugar, diced onion, BBQ sauce, ground mustard, black pepper, kosher salt, and the slice of bacon.
Stir all the ingredients thoroughly to ensure even distribution.
Place the baking dish in the preheated oven and bake for 90 minutes, uncovered.
Remove from the oven and serve using a slotted spoon.