Heat the oil up in a saucepan over medium heat. Add onion and garlic,
then cook, stirring occasionally, for about 5 minutes or until the
onion is tender. Add catsup, vinegar, brown sugar, jalapeno peppers,
salt, and mustard. Cook, stirring occasionally, until mixture is blended.
Place the chicken, skin side up, on a prepared grill about 8 inches
from the heat. Grill, turning every 8 to 10 minutes, for about 40
minutes. Brush chicken with sauce, grill, turning and basting with
sauce every 5 minutes, about 20 minutes more or until chicken is fork
tender. Source: "Chicken Cookery" 1994 Delmarva Chicken Cooking Contest