Preheat oven to 400°F. Fit an oven-safe wire rack inside a rimmed baking sheet and spray. Set aside.
Sprinkle the chicken pieces evenly with 1/2 teaspoon of the salt and 1/4 teaspoon of the pepper. Use a sharp knife to cut a pocket in each chicken breast without cutting all the way through the other side.
Place two slices of cheese on top of two slices of ham and tightly roll. Stuff inside the chicken breasts and secure the pocket with toothpicks.
Dredge: 1st Bowl - Whisk together flour, remaining salt and black pepper, granulated garlic and onion powder in a shallow bowl. 2nd Bowl - Beaten egg and milk. 3rd Bowl - Panko breadcrumbs and grated Parmesan cheese.
Working with 1 chicken breast at a time dredge in flour, then dip in egg wash letting excess drip off. Dredge in panko-parmesan to coat, pressing to adhere. Place on prepared wire rack.
Drizzle the chicken pieces with melted butter. Be gentle so as not to disturb the breading.
Bake for 25-30 minutes or until the juices run clear and an instant read thermometer registers 160°F when inserted into the thickest portion of the chicken. Broil at the end of baking to brown further.
Dijon Cream Sauce: Melt butter over medium heat in a small heavy bottomed saucepan. Whisk in flour, cooking for 1 minute. Next, whisk in cream, Dijon mustard, Parmesan cheese and nutmeg. Simmer on low for 3-5 minutes, stirring occasionally until thickened. The sauce will thicken further as it cools.
Serve Chicken Cordon Bleu drizzled with sauce garnished with fresh chives.
Notes
Breadcrumbs: If you're unable to find Italian seasoned panko breadcrumbs you can use plain breadcrumbs (regular breadcrumbs) and add 1 teaspoon of dry Italian seasoning to the mix.
Cheese: You can use sliced Swiss cheese or Gruyère cheese in this recipe. Wrapping the cheese inside of the ham slices helps to contain it so it doesn't escape while baking.
Ham: You can use honey ham, Virginia ham or smoked ham in this recipe.
Pan Options: You could also use a broiler pan to make this chicken.
Please Note: Nutritional data includes optional sauce.