Super-moist and delicious! The secret is the slow cooking on an un-lit side of the BBQ.
Put lemongrass, ginger, fish sauce,, lime juice, garlic, red pepper flakes and zest in a food processor to make a thick paste, adding water if needed. Spread mixture over chicken breasts, under the skin and on both sides. Cover and refrigerate for 1-4 hours. Pre-heat a gas grill on high heat. Turn off one burner and keep the other lit. Put the chicken on the un-lit side, cover and cook for 15 minutes, turn and cook for 35 minutes total.
1/2 cup minced lemongrass (Or 1 tube processed lemongrass)
3 T. peeled and grated fresh ginger
3-4 T. nuoc mam (Asian fish sauce)
3 T. fresh lime juice
3 cloves garlic, minced
1/2 - 1 tsp. red pepper flakes, as desired
Grated zest of 1 lime
2-3 T. water, if needed
4 large chicken breasts, skin on, bone in