01 - In a large mixing bowl, whisk together the buttermilk, olive oil, minced garlic, kosher salt, black pepper, paprika, dried thyme, lemon zest, and lemon juice until well combined.
02 - Place the spatchcocked or cut chicken into a large zip-top bag or non-reactive container. Pour the marinade over the chicken, ensuring every piece is thoroughly coated. Seal tightly and refrigerate for at least 8 hours or overnight for optimal flavor penetration.
03 - Remove the chicken from the marinade and allow excess to drip off. Discard the used marinade. Pat the chicken lightly with paper towels and brush evenly with olive oil.
04 - Preheat the oven to 425°F. Set the chicken on a wire rack placed over a rimmed baking sheet to allow even air circulation during roasting.
05 - Roast for 45 to 60 minutes, until the skin is deep golden brown and the juices run clear. Verify the internal temperature reaches 165°F in the thickest part of the thigh using a meat thermometer.
06 - Transfer the chicken to a cutting board and let it rest for 10 minutes to allow the juices to redistribute. Carve into serving pieces, garnish with fresh herbs if desired, and serve warm.