Prepare the Marinade: In a medium mixing bowl, combine the Dijon mustard, pure maple syrup, 2 tablespoons of olive oil, minced garlic, apple cider vinegar, dried thyme, smoked paprika, salt, and pepper. Whisk thoroughly until the mixture is well combined and smooth.
Marinate the Chicken: Place the chicken thighs into a large zip-lock bag or a shallow dish. Pour the marinade over the chicken, ensuring each piece is generously coated. Seal the bag or cover the dish and refrigerate for at least 30 minutes to allow the flavors to meld. For best results, marinate for up to 4 hours.
Preheat the Oven: Shortly before you're ready to cook, preheat your oven to 400°F (200°C) so it's ready for baking.
Sear the Chicken: In a large oven-safe skillet, heat a drizzle of olive oil over medium-high heat. Once the oil is shimmering, add the marinated chicken thighs (set the remaining marinade aside) to the skillet. Sear the chicken for about 3-4 minutes on each side, or until a beautiful golden-brown crust forms.
Add Vegetables: Lower the heat to medium, and introduce the sliced red bell pepper, halved cherry tomatoes, and baby spinach to the skillet. Mix the vegetables gently around the chicken, creating a vibrant bed for the meal.
Bake: Drizzle the reserved marinade evenly over the chicken and the vegetables in the skillet. Carefully transfer the skillet to your preheated oven and bake for 20-25 minutes, or until the chicken is fully cooked and reaches an internal temperature of 165°F (74°C).
Serve: Once baked, remove the skillet from the oven and let it rest for a few minutes. This will help the juices redistribute within the chicken.
Notes
For a rustic presentation, serve the dish directly from the skillet. Garnish with fresh thyme or chopped parsley.