Step 1

Whisk the buttermilk, sugar, garlic, lemon juice, paprika, salt, pepper, and red pepper flakes together in a large bowl or resealable plastic container.

Step 2

Add the chicken, making sure each piece is submerged. Cover and refrigerate for at least 8 hours or up to overnight.

Step 3

Light one half of a gas grill to medium-high heat (about 375°F). Alternatively, prepare a chimney's worth of charcoal and fill one half of a charcoal grill with lit charcoal. Cover the grill and heat for 20 minutes while you prepare the chicken.

Step 4

Remove the chicken from the marinade and pat dry with paper towels. When the grills is ready, place the chicken on the unlit side of the grill. Cover and cook for 20 minutes. Flip the chicken, cover, and cook for 20 minutes more. Check the chicken for doneness; it should register at least 165°F in the thickest piece. Grill for 10 minutes more if needed.

Step 5

Move the cooked chicken to the lit section of the grill and grill until the skin is crisp and charred, 4 to 5 minutes more. Transfer to a serving platter and let cool for 5 minutes before serving.