Preheat oven to 400 degrees F.
Slice each slice of bacon into 4 pieces. Cook in a large pot over medium heat, until fat is rendered, but bacon is not yet crispy.
In pan with bacon fat, cook chopped onion until soft, about 5 minutes. Add remaining ingredients, stir to combine. Bring to boil, then reduce heat and simmer for 10 minutes.
Carefully transfer with a ladle to a 2-quart casserole dish. Place on foil-lined baking sheet and bake 45 minutes to 1 hour, or until beans are desired thickness.