Preheat the oven to 400°F (200°C). Grease a baking dish with cooking spray.
Place the chicken breasts between two sheets of plastic wrap and pound them to an even thickness, about ½ inch thick.
Prepare the Breading Mixture
In a shallow bowl, mix together the grated Parmesan cheese, breadcrumbs, garlic powder, oregano, salt, and pepper.
In another bowl, whisk together the eggs and milk until well combined.
Coat the Chicken
Dip each chicken breast into the egg mixture, allowing the excess to drip off.
Coat the chicken in the breadcrumb mixture, pressing gently to adhere the coating evenly.
Bake the Chicken
Place the coated chicken breasts in the prepared baking dish and bake in the preheated oven for 25-30 minutes, or until the chicken is cooked through and the coating is golden brown.
Prepare the Cream Sauce
While the chicken is baking, combine the heavy cream and Dijon mustard in a saucepan over medium heat. Stir until heated through but not boiling.
Serve the Dish
Once the chicken is done, remove it from the oven and let it rest for a few minutes before slicing. Drizzle the cream sauce over the chicken and garnish with fresh parsley.