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 thoroughly 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 well 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 any excess to drip off. Discard the used marinade. Preheat the oven to 425°F. Place the chicken on a wire rack set over a rimmed baking sheet. Pat the surface lightly with paper towels and brush evenly with olive oil.
04 - Roast the chicken for 45 to 60 minutes, or until the skin is a deep golden brown and the juices run clear. The internal temperature in the thickest part of the thigh should register 165°F when checked with a meat thermometer.
05 - Transfer the chicken to a cutting board and let it rest for 10 minutes before carving. Garnish with fresh herbs if desired and serve warm.