In a medium bowl, whisk together olive oil, minced garlic, chopped rosemary, lemon zest, lemon juice, Dijon, honey, and red pepper flakes until smooth.

Season the chicken thighs generously with salt and pepper on both sides. Place them in a shallow dish or zip-top bag and pour the marinade over, turning to coat. Marinate at room temperature for 30 minutes, or refrigerate up to 8 hours for deeper flavor. If refrigerated, allow 20 minutes at room temperature before cooking.

Preheat oven to 400°F (200°C).

Heat a large ovenproof skillet over medium-high heat. Add 1 tablespoon olive oil.

Remove thighs from marinade (reserve the marinade) and place skin-side down in the hot pan. Sear 3 to 5 minutes until the skin is deeply golden and releases easily from the pan. Flip and sear the other side 1 to 2 minutes.

Pour the reserved marinade and 1/4 cup chicken stock or white wine into the skillet around the chicken (not directly on skin). Add a few sprigs of rosemary and lemon slices if desired.

Transfer the skillet to the preheated oven and roast 20 to 30 minutes, or until the internal temperature reaches 165°F (74°C) and juices run clear. The skin should look crisp and the meat should be tender when pierced.

Transfer chicken to a plate and tent loosely with foil to rest for 5 minutes.

Place the skillet on the stovetop over medium heat. Add an extra splash of stock if the pan is dry and scrape up browned bits with a wooden spoon. Simmer 1 to 2 minutes to concentrate flavors, then finish with a squeeze of lemon juice and adjust salt and pepper.

Spoon the sauce over the chicken and garnish with fresh rosemary and lemon wedges.