Prepare the Honey Mustard Sauce: In a bowl, whisk together Dijon mustard, honey, olive oil, and a dash of Herbes de Provence. Set aside.
Season the Chicken: Season chicken breasts with salt, pepper, and a light sprinkle of Herbes de Provence for a French herb infusion.
Sear the Chicken: In a skillet over medium heat, add olive oil and sear the chicken breasts until golden brown, about 5 minutes per side.
Prepare the Bacon and Mushrooms: In a separate skillet, cook bacon until crispy. Remove and set aside. Add sliced mushrooms to the same skillet and sauté until tender.
Assemble the Chicken: Place seared chicken breasts on a baking sheet. Layer each breast with crispy bacon, sautéed mushrooms, a generous drizzle of honey-mustard sauce, and top with shredded Gruyère cheese.
Bake: Bake in a preheated oven at 350°F (175°C) for 15 minutes, or until the cheese is melted and bubbly.
Garnish and Serve: Remove from the oven, garnish with chopped fresh parsley, and serve hot with your favorite side.