blend together 1 C yogurt and remaining marinade ingredients in food processor until smooth. Transfer to a lg. bowl. whisk in remaining 1 C yogurt. add chicken and turn to coat. cover with plastic wrap and let marinade in the refrigerator overnight

light charcoal fire on high.

remove chicken from marinade and place on grill grate. cook until no longer pink at the bone about 12 min. per side occasionally basting with butter the last 2 min.

transfer chicken to a platter and top with onion rings and cilantro