Put the beans in a stockpot or Dutch oven. Add water to cover by several inches. Bring to a boil over high heat. Remove from the heat, cover and set aside for 1 hour. Drain the beans and return them to the stockpot. Add the broth to just cover the beans (add water if needed). Bring to a boil over high heat. Reduce the heat and simmer, covered, for about 1 hour 15 minutes, or until tender, adding water if needed to keep the beans just covered. When the beans start to simmer, mince the onion. Lightly spray a large skillet with vegetable oil spray. Cook the onion over medium-high heat for about 5 minutes, or until softened and browned. Stir the onion, brown sugar, Worcestershire sauce, chili powder, pepper and mustard into the beans. Leave the beans uncovered for the remainder of their cooking time. When the beans are tender, stir in the tomato sauce and vinegar. |