Hoisin Barbecue Sauce

Heat the vegetable oil in a small saucepan and cook the garlic over moderately low heat until fragrant, about 2 minutes. Add the hoisin sauce, soy sauce, sake, ketchup and rice vinegar and simmer over moderately low heat, stirring, until thickened, about 3 minutes. Remove from the heat and stir in the sesame oil. Let cool and serve.