Season chicken with salt and pepper. Combine with half the minced garlic, half the parsley, lemon zest from one lemon, olive oil, and juice from 1 lemon. Marinate for 1-3 hours.
Preheat the grill to high heat. Saute butter over medium-low heat. Add the rest of the garlic, parsley, and peppercorn. Saute for about 3 minutes. Squeeze in the juice from half a lemon and remove from the heat.
Place chicken on the grill and sear for 3 minutes. Place a half lemon on the grill as well. Flip the chicken sear for another 2 minutes. Turn one burner off and move the chicken to indirect heat. Cook each side for another 6 minutes. Use a cooking brush to brush on the sauce occasionally.
Once the chicken reaches 165 -185 degrees F remove from the grill. Squeeze the lemon juice over the chicken and serve.
Notes
1. Make sure to get a good sear on the chicken before placing it in indirect heat.2. I like to cook chicken thighs to about 180 degrees F. The texture at 165 can be a little soft and fatty. 180 is the perfect temperature.