Start by flattening the chicken breasts to about half an inch thick using a meat mallet or rolling pin. This helps them cook evenly and quickly.
Season both sides of the flattened chicken breasts with salt, pepper, onion powder, and Italian seasoning.
In a large skillet, melt 2 tablespoons of butter over medium-high heat.
Add the seasoned chicken breasts to the skillet and cook for about 3-4 minutes on each side, or until golden brown and cooked through. Cook in batches if needed to avoid overcrowding the pan.
Once the chicken is cooked, transfer it to a plate and keep warm.
In the same skillet, add the remaining 2 tablespoons of butter and minced garlic. Sauté for about 1-2 minutes, until the garlic is fragrant and slightly golden but not burned.
Lower the heat and return the chicken to the skillet, spooning the garlic butter over the top. Immediately sprinkle the grated Parmesan cheese on each piece of chicken.
Cover the skillet for about 1-2 minutes, allowing the cheese to melt and become bubbly.
Remove from heat, garnish with fresh chopped parsley, and serve immediately.