Thai Grilled Chicken - Gai Yang Hot and Sweet Dipping Sauce - Nam Jeem Guy Yang

With a cleaver or poultry shears halve chicken breasts and cut each half crosswise into 4 pieces. With a mortar and pestle, or flat side with the sharp edge of the cleaver, blend peppercorns and garlic with a pinch salt to a smooth paste. Add coriander roots and pound or blend to a paste. In a large non-metallic bowl stir together coriander paste, fish sauce, and coconut milk. Add chicken and turn to coat well with marinade. Marinate chicken, covered, at room temperature 1 hour, or for several hours in refrigerator. Prepare grill (or preheat broiler). Grill chicken, skin sides down, on a lightly oiled rack set 5 to 6 inches over glowing coals until browned, 7 to 10 minutes. Brush top of chicken lightly with marinade, discarding any remaining marinade, and turn chicken. Grill chicken until just cooked through and juices run clear, 7 to 10 minutes more. (Alternatively, chicken may be broiled in same manner on lightly oiled rack of a large broiler pan about 4 to 6 inches from heat.) Serve chicken with dipping sauce and cooked rice. In a small saucepan bring vinegar to a boil. Stir in sugar and simmer 5 minutes. Remove from heat and stir garlic paste and red pepper flakes into vinegar. Cool. Serve sauce at room temperature in individual condiment bowls for dipping.