‘Christmas Dinner Backup’: Just 4 ingredients. I make this every Christmas when I need something foolproof.

This incredibly simple dinner yields a rich, bistro-style flavor with minimal effort. The combination of French onion soup and melted Swiss cheese creates a savory sauce that is perfect for serving over rice or mashed potatoes.

4-Ingredient French Onion Chicken Casserole

Ingredients:

How To Make 4-Ingredient French Onion Chicken Casserole:

Step 1: Prep the Oven and Dish: Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish or a similar oven-safe casserole dish to prevent sticking.

Step 2: Prepare the Chicken: Pat the 1 1/2 to 2 lbs of chicken dry with paper towels and trim away any excess fat. Arrange the pieces in a single, even layer in the bottom of your prepared baking dish.

Step 3: Whisk the Sauce: In a medium mixing bowl, whisk together the 10 1/2 oz can of cream of chicken soup and the 10 1/2 oz can of French onion soup. Whisk until the mixture is smooth and fully combined. Note: Do not add water or milk; the condensed soups will create a thick, savory gravy as they bake.

Step 4: Coat the Chicken: Pour the soup mixture evenly over the chicken. Use a spoon or spatula to ensure each piece is well-coated and the sauce is distributed into the corners of the pan.

Step 5: First Bake: Cover the baking dish tightly with aluminum foil. Bake for 25–30 minutes, or until the chicken is cooked through (reaching an internal temperature of 165°F).

Step 6: Melt the Cheese: Carefully remove the foil. Sprinkle the 1 1/2 cups of shredded Swiss or Gruyere cheese evenly over the top. Return the dish to the oven, uncovered, and bake for another 10–15 minutes until the cheese is melted, bubbly, and slightly golden.

Step 7: Rest and Serve: Remove from the oven and let the casserole rest for 5–10 minutes to allow the sauce to thicken slightly. Serve warm, spooning plenty of the oniony gravy over the chicken.