French Onion Chicken Bake

Preheat your oven to 375°F (190°C).
In a large skillet over medium heat, melt the butter with the olive oil. Add the sliced onions and cook slowly, stirring often, for about 15–20 minutes until deeply caramelized.
Stir in the minced garlic, beef broth, balsamic vinegar, and dried thyme. Let the mixture simmer for 2–3 minutes until slightly thickened.
Place the chicken breasts in a greased baking dish and season them with salt and pepper.
Pour the caramelized onion mixture evenly over the chicken.
Top each chicken breast with a generous layer of shredded cheese.
Bake uncovered for 25–30 minutes, or until the chicken is fully cooked and the cheese is golden and bubbly.
Garnish with freshly chopped parsley before serving, if desired.

Add mushrooms: Sauté sliced mushrooms along with the onions for an earthier depth.
Cheese options: Swap mozzarella for Gruyère or Swiss for a more authentic French onion flavor.
Low-carb friendly: Serve with roasted vegetables or cauliflower mash.
Creamy version: Stir in a couple of tablespoons of cream to the broth mixture before pouring over the chicken.

For perfectly caramelized onions, take your time—low and slow is key.
To ensure even cooking, pound chicken breasts to uniform thickness or use chicken thighs for extra juiciness.
Leftovers reheat beautifully and can even be used as a sandwich filling or over pasta the next day.
If the cheese browns too quickly, cover loosely with foil for the final few minutes.