Heat oil in a cooking pot.
Add onions. Cook until the onions gets soft and somewhat caramelized.
Add bacon. Cook for 1 minutes.
Pour the tomato sauce, vinegar, and liquid from the can of beans into the pot. Add mustard powder. Let boil. Stir and cover. Continue to cook in low heat for 30 to 35 minutes. Note: add water if the liquid starts to dry-up.
Add the molasses, beans, and salt into the pot. Gently stir. Cover and cook for 8 to 10 minutes.
Transfer to serving bowl. Serve.
Share and enjoy!