Cook beans in water while preparing the other ingredients. Fill pot up with water till 2" above the beans and simmer till tender. Saute the onions in oil for a few minutes, then add the salt, chili powder, cumin, and dry mustard. Continue to cook over medium heat for 6-8 minutes. Add garlic and cook for 5 more minutes.
Saute the onions in oil for a few minutes, then add the salt, chili powder, cumin, and dry mustard. Continue to cook over medium heat for 6-8 minutes. Add garlic and cook for 5 more minutes.
Add the vinegar, molasses and tomatoes and mix well. I like to blend the tomatoes so there are not so many big chunks, but that's completely up to you. Add in the cooked and drained beans and mix.
Preheat the oven to 350 degrees. Pour the mixture into a 8x8 dish. and cover with tin foil. Bake for 60 minutes then remove the foil and cook for another 10-20 minutes if you would like it thicker.
If you want you can then top with the grated cheese and bake till melted. Serve with warm cornbread or even over brown rice with a veggie on the side.