Heat oil in 2-quart saucepan over medium heat. Add onion and garlic; saut‚ until softened, 4-5 minutes. Stir in all the remaining ingredients except ketchup; bring to a boil. Reduce heat to low, then add ketchup. Cook, stirring occasionally, until thickened, about 15 minutes.

Served originally at Mama Rosa's, a long-time barbecue pit restaurant in North Philadelphia, this recipe is adapted from Jim Tarantino's outstanding book "Marinades" (Crossing Press, 1992).