Caramelize the Onions
In a large skillet over medium heat, melt the butter and add the sliced onions. Cook, stirring occasionally, for about 20-25 minutes until the onions are golden brown. If they begin to stick, add a splash of water or beef broth to deglaze the pan.
Add Garlic and Seasonings
Stir in the minced garlic, sugar, and balsamic vinegar. Cook for an additional 2-3 minutes to blend the flavors.
Deglaze the Pan
Pour in the white wine and beef broth, scraping up any browned bits from the bottom of the skillet. Let the mixture simmer for about 5 minutes until the liquid reduces slightly.
Prepare the Chicken
While the onions are cooking, preheat your oven to 375°F (190°C). Season the chicken breasts with salt and pepper. In a separate oven-safe skillet, heat the olive oil over medium-high heat. Sear the chicken breasts for 2-3 minutes on each side until they develop a golden crust.
Combine and Bake
Transfer the caramelized onion mixture over the seared chicken breasts in the oven-safe skillet. Sprinkle the shredded Gruyère cheese evenly over the top.
Bake
Place the skillet in the preheated oven and bake for 20-25 minutes, or until the chicken is cooked through and the cheese is melted and bubbly.
Garnish and Serve
Remove from the oven, garnish with chopped fresh parsley, and serve hot.
Notes
Ingredient Quality
Using high-quality olive oil and unsalted butter will enhance the flavor of the dish significantly.
Cheese Variations
If Gruyère cheese is unavailable, you can substitute it with Swiss cheese or a mix of mozzarella and Parmesan for a different flavor profile.
Chicken Alternatives
This recipe can also be adapted for bone-in chicken pieces; just increase the cooking time as needed to ensure thorough cooking.
Serving Suggestions
Serve this dish with a side of crusty bread, mashed potatoes, or a fresh green salad to balance the richness.
