Begin by placing your bone-in, skin-on chicken pieces into a large ziplock bag. Pour in buttermilk and Dijon mustard, ensuring the chicken is thoroughly coated. Seal the bag and refrigerate for at least 2 hours, or for maximum tenderness and flavor, let it marinate overnight.

Preheat your oven to 400°F (200°C). In a food processor, add freshly minced garlic, breadcrumbs, thyme, lemon zest, salt, and pepper. Pulse until they’re well combined, then slowly drizzle in olive oil while continuing to blend, transforming the mixture into a cohesive, textured coating. Set it aside.

Take the marinated chicken out of the fridge, allowing the excess buttermilk mixture to drip off. Spread the breadcrumb mixture onto a shallow dish, then press each chicken piece, skin-side down, firmly into the crumbs, ensuring a generous coating.

Line a baking sheet with foil for easy cleanup, then place the coated chicken skin-side up on the sheet. Bake for 40 minutes until the skin is golden and crispy, and the internal temperature reaches 165°F (75°C).