Preheat the oven to 350 degrees F.
Fry the bacon in a large skillet over medium-high heat until crisp. Remove the bacon from the pan, leaving the drippings, and drain it on paper towels. Crumble and set aside.
Add the onion to the pan with the bacon drippings and saute until softened, a couple minutes. Stir in the beans, molasses, brown sugar, mustard and crumbled bacon, and mix well.
Pour the beans into a 3-quart casserole and bake, uncovered, for about 45 minutes.
Adapted from "Georgia Cooking in an Oklahoma Kitchen" by Trisha Yearwood (c) Clarkson Potter 2008. Provided courtesy of Trisha Yearwood. All rights reserved.