Begin by tenderizing the chicken breasts. Place each breast between two sheets of plastic wrap and gently pound them to an even thickness of about half an inch using a meat mallet or rolling pin.
Generously season both sides of the flattened chicken breasts with salt, freshly cracked black pepper, onion powder, and Italian seasoning.
In a large skillet, heat 2 tablespoons of unsalted butter over medium-high heat until melted and sizzling.
Carefully add the seasoned chicken breasts to the skillet. Cook for approximately 3-4 minutes on each side, or until they are golden brown and cooked through.
Once cooked, transfer the chicken breasts to a plate and cover them with aluminum foil to keep warm while you prepare the sauce.
In the same skillet, add the remaining 2 tablespoons of butter and the minced garlic. Sauté for about 1-2 minutes until the garlic is fragrant and lightly golden.
Reduce the heat to low and return the chicken to the skillet. Spoon the garlic butter generously over the top of each piece and sprinkle the grated Parmesan cheese on top.
Cover the skillet with a lid and let it cook for an additional 1-2 minutes to help the cheese melt.
Remove the skillet from heat and garnish the chicken with fresh chopped parsley. Serve immediately.