Thai Grilled Chicken with Sweet & Spicy Dipping Sauce

To prepare chicken: Combine garlic cloves, pepper, cilantro stems and pinch of salt in a large mortar or food processor or food mill and mash or pulse to a coarse paste. Transfer to a large bowl; stir in fish sauce and coconut milk. Add chicken and stir to coat with the marinade. Refrigerate, loosely covered, for at least 30 minutes and up to 1 hour.

Preheat grill to medium. (No grill? See broiler variation, below.)

To prepare sauce: Heat vinegar to a boil in a small nonreactive pan. Add sugar, stir to dissolve it, then reduce heat and simmer for 3 to 4 minutes. Add crushed red pepper and minced garlic; simmer for 1 minute more. Remove from the heat and stir in salt. Pour into a serving bowl and let cool to room temperature before serving.

Remove the chicken from the marinade. (Discard marinade.) Oil the grill rack (see Tips). Grill, turning occasionally, until golden brown and an instant-read thermometer inserted into the thickest part without touching bone registers 165°F, 15 to 20 minutes.

Serve the chicken with the dipping sauce.