Preheat oven to 325 degrees. Gather your ingredients so that you have everything close at hand on the counter or table.
Chop the sweet onion into small pieces.
Prepare the Beans
In a medium bowl, add the pork-n-beans, brown sugar, ketchup, mustard, and diced onions. Season with kosher salt and freshly ground black pepper. Mix to combine.
Pour beans into a greased baking dish.
Add the Bacon
If desired, cook bacon in a large skillet until lightly browned. You may either chop the bacon into bite-size pieces or leave in strips. Top the beans with the bacon.
Bake for 2 -2 1/2 hours until the sauce is thick and bubbly. Allow to cool for 10-12 minutes before serving. Serves 6-8.