Embarking on your Chicken Cordon Bleu Casserole adventure is simple! Follow these easy steps:

1. Preheat the Oven: Start by preheating your oven to 350°F (175°C).
2. Prepare Baking Dish: Grease a 9×13 inch baking dish with cooking spray or butter.
3. Combine Chicken and Ham: In a large bowl, mix the shredded chicken and diced ham until well combined.
4. Add Cheese: Stir in the shredded Swiss cheese, ensuring an even distribution.
5. Mix Soup and Milk: In another bowl, whisk together the cream of chicken soup, milk, Dijon mustard, garlic powder, salt, and pepper until smooth.
6. Combine Mixtures: Pour the soup mixture over the chicken and ham mixture. Stir gently to coat everything evenly.
7. Transfer to Baking Dish: Pour the combined mixture into the greased baking dish, spreading it evenly.
8. Top with Breadcrumbs: Sprinkle breadcrumbs evenly over the casserole for a crispy topping.
9. Bake: Place the dish in the preheated oven and bake for 30-35 minutes or until bubbly and golden brown on top.
10. Garnish: Once baked, let it cool for a few minutes, then sprinkle chopped parsley on top for added color before serving.

These step-by-step instructions will guide you seamlessly through making this incredible casserole!