Finely chop the onion and mince the garlic. Peel the sweet potatoes and cut them into 1-inch cubes.
Heat the oil in a medium-size saucepan over medium heat. Add the onion and sauté, stirring on occasion, until the onion begins to wilt, about 5 minutes.
Add the sweet potatoes, garlic, spices, tomato sauce, peanut butter, broth, and beans with their liquid