Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper for easy cleanup.
In a shallow bowl, mix together the grated Parmesan cheese, breadcrumbs, chopped parsley, garlic powder, onion powder, black pepper, and salt until well combined.
In a separate bowl, whisk the eggs and add the Dijon mustard if using, mixing until smooth.
Take each chicken breast and dip it first into the egg mixture, allowing any excess to drip off.
Next, coat the chicken in the Parmesan breadcrumb mixture, pressing gently to adhere the coating well to the chicken.
Heat the olive oil in a large skillet over medium heat. Once hot, add the coated chicken breasts and sear for about 2-3 minutes on each side, or until golden brown.
Transfer the seared chicken breasts to the prepared baking sheet and bake in the preheated oven for 15-20 minutes, or until the chicken is cooked through (internal temperature should reach 165°F or 74°C).
Remove from the oven and let rest for a few minutes before slicing.
Notes
Serve on a wooden cutting board with fresh parsley and lemon wedges.