Buttermilk Grilled Chicken

Combine buttermilk, brown sugar, cider vinegar, garlic, thyme, pepper, paprika, cumin, cayenne, and salt in a bowl to create the marinade.

Cut along both sides of the chicken's backbone, from the tail to the neck, and carefully remove it. Make a 1/4-inch-deep incision through the cartilage in the center to expose the breastbone. Lift out the backbone and divide the chicken into two halves along its center line.

Place both chicken halves in a resealable zip-top bag and pour the marinade over them. Position the bag inside another bowl to capture any spills, then press out as much air as possible and seal it tightly. Refrigerate for 6 to 18 hours.

Preheat the outdoor grill to medium heat and lightly grease the grates with oil. Remove the chicken from its marinade and transfer it to a paper towel-lined plate, allowing any excess liquid to drip off.

Place the chicken on the grill with its cut-side facing down and skin-side up. Cover the grill and cook for 20 minutes.

Flip the chicken over and continue grilling for an additional 7 to 10 minutes. Flip it once more and grill until the chicken is no longer pink in its center, approximately 15 minutes. Use an instant-read thermometer to check the internal temperature of the thickest part of the thigh, near the bone; it should reach 165 degrees F (74 degrees C).