Grilled Indian-Spiced Butter Chicken

PreparationMarinate chicken: Purée onion, garlic, ginger, salt, chile, and vinegar to a smooth paste in a food processor. Transfer to a large wide bowl and whisk in yogurt, coriander, oil, turmeric, and cayenne. Add chicken pieces and turn to coat thickly. Cover with plastic wrap and marinate, chilled, at least 16 hours. Let stand at room temperature 30 minutes before grilling. Make ghee: Bring butter to a boil in a 1-quart heavy saucepan over moderate heat. When foam completely covers butter, reduce heat to very low. Cook butter until a very thin crust begins to form on surface and milky white solids fall to bottom of pan, about 8 minutes. Continue to cook butter, watching constantly, until solids at bottom of pan turn light brown and butter has a nutty fragrance, 8 to 16 minutes. Remove pan from heat and let butter stand 1 minute. Pour through a sieve lined with a dampened heavy-duty paper towel or a triple layer of cheesecloth into a bowl, discarding solids. Prepare grill for cooking over indirect heat with medium-hot charcoal (moderate heat for gas); see Grilling Procedure . To cook chicken using a charcoal grill: Lightly oil grill rack. Put chicken (still heavily coated with marinade) on rack over area of grill with no coals underneath. Drizzle chicken with about 1 tablespoon ghee. Cook chicken over medium-high heat, turning over and drizzling with ghee every 5 minutes, until cooked through, 20 to 25 minutes. To cook chicken using a gas grill: Lightly oil grill rack. Put chicken over shut-off burner. Cook chicken, turning over and drizzling with ghee every 5 minutes, until cooked through, about 20 to 25 minutes. (Cover grill between turns.) Serve chicken drizzled with any remaining ghee. Cooks' notes:· To get 1/3 cup thick yogurt, drain 2/3 cup regular plain yogurt in a fine-mesh sieve, chilled, at least 8 hours. · If you aren't able to grill outdoors, chicken can be broiled on rack of a broiler pan 3 inches from heat. Drizzle some of ghee on chicken and broil, turning and drizzling with ghee every 5 minutes, until chicken is cooked through, about 25 minutes. · Chicken can be marinated up to 3 days. · Ghee, covered and chilled, keeps up to 1 month. Melt before using.