Heat oven to 325°. Grease a 2 1/2- to 3-quart baking dish.
Fry the bacon until done but not crisp. With a slotted spatula or spoon, remove to paper towels to drain. In the drippings, cook the onion and bell pepper until tender, 4 to 5 minutes. Add the beans and stir to blend. Continue cooking, stirring occasionally, for 5 minutes. Transfer to the prepared baking pan, top with the bacon pieces, and bake until bubbly and thickened, about 1 1/2 to 2 hours.
Calories per serving: 369