Preheat the oven: Set your oven to 400°F (200°C). Place a large oven-safe skillet (12-inch) on the stove.

Season the chicken: Pat the chicken thighs dry and season both sides generously with salt and pepper.

Sear for flavor: Heat 2 tablespoons of olive oil over medium-high heat. Add the chicken and sear 3–4 minutes per side until lightly golden. The chicken doesn’t need to be cooked through yet. Transfer to a plate.

Sauté the garlic: Lower the heat to medium. Add the remaining 1 tablespoon of olive oil. Add minced garlic and cook 30–45 seconds, just until fragrant. Don’t let it burn.

Add the marinara: Pour in the marinara sauce. Stir in Italian seasoning and red pepper flakes. Simmer for 1–2 minutes to warm and blend flavors.

Nestle the chicken: Return the seared thighs to the skillet, coating each piece with sauce. Keep them in a single layer for even cooking.

Toast the breadcrumbs: In a small bowl, mix breadcrumbs, Parmesan, and melted butter (if using). Sprinkle the mixture evenly over the chicken. This topping will crisp up in the oven.

Bake: Transfer the skillet to the oven. Bake for 12–15 minutes, until the chicken reaches 165°F (74°C) at the thickest part.

Add the cheese: Remove the skillet, sprinkle mozzarella over the chicken, and return to the oven for 3–5 minutes, until melted and bubbly. For extra browning, broil on high for 1–2 minutes. Watch closely.

Rest and garnish: Let the chicken rest for 5 minutes. Top with chopped basil or parsley. Serve hot with the saucy skillet juices.