French Onion-Chicken Casserole is a comforting and flavorful dish that combines the classic flavors of French onion soup with tender chicken and melted cheese. The chicken is seasoned with salt, pepper, and thyme, then seared until golden brown. It is then topped with caramelized onions, beef broth, and Gruyere cheese before being baked in the oven until bubbly and golden. Serve this casserole with a side of crusty bread for a satisfying and delicious meal.