Preheat the oven: Heat to 425°F (220°C). Line a rimmed sheet pan with foil or parchment for easy cleanup. Set a wire rack on top if you want extra-crispy skin.

Pat the chicken dry: Use paper towels to remove surface moisture. Dry skin browns better and gets crisp.

Season the thighs: Sprinkle both sides with a little kosher salt and black pepper. Don’t skip this—it builds flavor from the start.

Make the sauce: In a bowl, whisk together olive oil, Dijon, whole-grain mustard, honey, garlic, apple cider vinegar, smoked paprika, thyme, 1/2 teaspoon salt, black pepper, and red pepper flakes if using.

Coat the chicken: Place the thighs skin-side up on the pan. Spoon about half the sauce under the skin and rub some on the flesh. Brush more sauce over the top, but leave a bit for basting later.

Roast: Bake for 30–35 minutes, until the chicken reaches 175–185°F in the thickest part. Thighs are forgiving and taste best a little higher than 165°F.

Baste and finish: Halfway through, spoon some pan juices over the thighs. In the last 5 minutes, brush on the remaining sauce and return to the oven so it glazes.

Broil for color (optional): Broil on high for 1–2 minutes to deepen the caramelization. Watch closely—sugar in the honey browns fast.

Rest and serve: Let the chicken rest 5 minutes. Garnish with chopped parsley and serve with lemon wedges if you like a bright finish.