Mix all marinade ingredients together in a large bowl, making sure the brown sugar is dissolved.
Trim chicken thighs of any visible fat using kitchen shears. Place trimmed chicken into a large ziploc bag and cover with marinade. Seal and place into refrigerator at least 4 hours, or overnight is best.
Preheat grill to 350 deg. Reduce heat to low on one burner. Place an oven-safe dish over the low burner and put stick of butter and green onions inside to slowly melt together.
Remove chicken from marinade and discard any remaining marinade.
Grill chicken thighs over medium heat, until cooked through. When each piece is done, place it into the butter and green onion bath, turning a couple of times to make sure it is well coated. Continue to grill remaining chicken and add as done to the butter bath, piling up the already coated pieces to one side until everyone is in the pool.
Suggested sides would be steamed rice, green salad and sliced fresh pineapple for a meal that will transport you to the islands!!