Baked Chicken Thermidor is a classic French dish that features tender chicken breasts smothered in a creamy mushroom and cheese sauce. The chicken is first seared to lock in the juices, then baked to perfection. The sauce is made with sautéed mushrooms, onions, garlic, white wine, and a blend of Gruyere and Parmesan cheese. This rich and flavorful dish is perfect for a special occasion or a fancy dinner party.