1 small red onion, thinly sliced crosswise and separated
1/4 cup chopped fresh cilantro
Process 1 cup yogurt and remaining marinade ingredients together in a food processor until smooth. Transfer to a large bowl. Whisk in remaining 1 cup yogurt. Add chicken and turn to coat. Cover with plastic wrap and let marinate in the refrigerator overnight.
Light a charcoal fire or preheat your gas grill on high. Oil the grate. Let the coals burn down to a medium-hot fire or adjust the gas grill burners to medium-high.
Remove chicken from marinade and place it grill grate. Cook until no longer pink at the bone, about 12 minutes per side, occasionally basting with butter during the last 2 minutes.
Transfer the chicken to a platter, top with the onion rings and cilantro, and serve.
Recipe reprinted with permission from Fred Thompson's Barbecue Nation: 350 Hot-Off-the-Grill, Tried-and-True Recipes from America's Backyard (Taunton Press, 2007).