1-First Step: Preheat and Prepare the Dish Start by preheating your oven to 350 degrees Fahrenheit and spraying a 9×13 casserole dish with cooking spray. This step sets the stage for even baking and prevents sticking, making cleanup easier. Layer the 5 1/2 cups of shredded rotisserie chicken evenly on the bottom of the dish as your base.

2-Second Step: Add the Ham Layer Next, add the 2 cups of cubed ham on top of the chicken layer. This builds the classic flavors of chicken cordon bleu casserole, creating a hearty foundation that’s simple yet effective. Ensure the ham is evenly distributed for consistent taste in every bite.

3-Third Step: Make the Cheese Sauce Now, focus on the cheese sauce by melting 4 tablespoons of butter over medium heat in a saucepan. Sprinkle 1/4 cup of all-purpose flour on top and cook for 1-2 minutes until it’s dry and clumpy, forming a roux. Slowly whisk in 2 cups of milk, then incorporate 1 tablespoon of Dijon mustard, 1 tablespoon of lemon juice, 1/2 teaspoon of garlic powder, and 1/4 teaspoon of salt. Simmer the mixture while whisking for 3-5 minutes until it thickens to a gravy-like consistency. For dietary adaptations, use gluten-free flour here if needed. This sauce is the glue that holds your chicken cordon bleu casserole together, adding creaminess and flavor.

4-Fourth Step: Incorporate Cheeses and Pour Over Layers Once thickened, remove the sauce from heat and stir in 1 1/4 cups of shredded Swiss cheese and 1/4 cup of grated Parmesan cheese until smooth. Adjust salt to taste for the perfect seasoning. Pour this sauce evenly over the ham and chicken layers in the dish, ensuring everything is covered for a moist, flavorful result.

5-Fifth Step: Prepare and Add the Topping Mix 1 cup of Panko bread crumbs with 2 tablespoons of melted butter in a small bowl. For variations, you could use regular breadcrumbs if Panko isn’t on hand. Sprinkle this mixture evenly over the casserole to create a crunchy topping that contrasts the creamy interior.

6-Final Step: Bake and Serve Bake the casserole uncovered for 30-35 minutes, or until the topping turns golden brown and the dish is bubbly throughout. Let it cool for 5-10 minutes before serving to allow flavors to meld. This chicken cordon bleu casserole pairs well with sides like rice or vegetables, and for a sweet touch, consider trying this banana bread coffee cake recipe from our site for a delightful dessert option.