- 2 tablespoons vegetable oil
- 1 small white onion, diced small
- 3 garlic cloves, finely chopped
- 1 can (6 ounces) tomato paste
- 2 teaspoons ground mustard
- 1 can (28 ounces) tomato sauce
- 1/4 cup unsulfered molasses
- 2 tablespoons Worcestershire sauce
- 3 tablespoons white vinegar
- 2 teaspoons coarse salt
- 1 1/2 teaspoons ground pepper
- In a medium saucepan, heat oil over medium. Add onion and cook until completely soft, about 5 minutes. Add garlic and cook until fragrant, 1 minute.
- Add tomato paste and mustard; cook, stirring constantly, until paste turns a brick-red color, about 5 minutes. Add 2 cups water, tomato sauce, molasses, Worcestershire, vinegar, salt, and pepper and stir until smooth.
- Bring to a simmer; reduce heat to low and partially cover. Simmer, stirring occasionally, for 2 hours (thin with water if sauce becomes too thick). Season to taste with vinegar, salt, and pepper. Let cool completely before using.