Preheat your oven to 375°F. In a large skillet, heat the oil. Add the ground beef to the hot skillet and cook, stirring occasionally, until it's browned and crumbly, about 5 to 7 minutes.
Add the baked beans, cannellini beans, kidney beans, ketchup, brown sugar, onion powder, salt, pepper, vinegar, and mustard to the skillet. Stir to combine and bring to a gentle simmer.
Transfer the bean mixture to a casserole dish and spread it evenly. Cover with foil and bake until bubbly, about 25-30 minutes.