Combine oil, butter, onion powder, garlic powder, cumin, and lemon juice in large shallow pan. Add chicken halves, turning to coat well. Cover and marinate several hours or overnight.
Remove chicken from marinade, cook over medium coals on barbeque grill, or 4- inches from source of heat under broiler, until browned on both side and meat is done, turning and basting frequently, about 30 minutes.
Cut chicken halves into pieces to serve with beans and rice, corn or flour tortillas and salsa, if desired. Makes 6 servings.