Prepare the Chicken:

• Preheat the oven to 400°F (200°C). Lightly grease a baking dish or line it with parchment paper.
• Place each chicken breast between two sheets of plastic wrap or parchment paper. Using a meat mallet or rolling pin, pound the chicken to an even thickness of about 1/4 inch.
• Season both sides of the chicken breasts with salt and pepper.
• Lay a slice of ham and a slice of Swiss cheese on each chicken breast. Roll up each chicken breast tightly, starting from the narrower end, and secure with toothpicks.

Bread the Chicken:

• In a shallow bowl, mix the flour and paprika.
• In a separate bowl, whisk together the eggs and milk.
• In a third bowl, combine the breadcrumbs and grated Parmesan cheese.
• Dredge each chicken roll in the flour mixture, shaking off any excess. Dip into the egg mixture, then coat evenly with the breadcrumb mixture.

Cook the Chicken:

• In a large oven-safe skillet, melt the butter over medium heat. Add the breaded chicken rolls and cook until golden brown on all sides, about 4-5 minutes per side.
• Transfer the skillet to the preheated oven and bake for 20-25 minutes, or until the chicken is cooked through and the internal temperature reaches 165°F (74°C).

Prepare the Dijon Cream Sauce:

• While the chicken is baking, melt the butter in a saucepan over medium heat. Add the flour and whisk continuously for about 1 minute to form a roux.
• Gradually whisk in the milk, ensuring a smooth mixture. Continue to cook, stirring frequently, until the sauce thickens, about 3-5 minutes.
• Stir in the Dijon mustard, garlic powder, and grated Parmesan cheese. Season with salt and freshly ground black pepper to taste. Keep the sauce warm over low heat, stirring occasionally.

Serve:

• Once the chicken is done, remove the toothpicks and place each roll on a serving plate.
• Generously spoon the warm Dijon cream sauce over each chicken roll.
• Garnish with freshly chopped parsley, if desired, and serve immediately.