Preheat oven to 350°F.
In a large (6-quart) cast-iron or enameled Dutch oven, heat oil over medium-high heat. Add onions and cook until softened, 10 to 15 minutes. Add the “beefy” crumbles, if using, and cook, stirring occasionally, until the crumbles have thawed, about 3 minutes. Add tomatoes, beans, soup, and chili powder.
Stir well, transfer to oven, and bake, uncovered, for 1 hour, stirring every 30 minutes, until it cooks down to chili consistency.
