Place chicken breasts and Italian salad dressing into a large zip-top bag, and marinate for at least 2 hours.

Preheat oven to 475°F. Remove chicken from marinade and allow to come to room temperature.

In a small bowl, combine shredded cheese and ranch dressing. Set aside.

In a separate small bowl, stir melted butter, panko breadcrumbs, garlic salt, and parsley flakes. Set aside.

Heat olive oil in an oven-safe skillet over medium-high heat.

Add chicken to skillet and cook for 4-5 minutes per side until browned and internal temperature reaches 165°F.

Turn off heat. Spread cheese mixture over chicken breasts.

Top each with 2 tablespoons of breadcrumb mixture.

Transfer skillet to oven and bake for 8-10 minutes until cheese is melted and breadcrumbs are crispy.

Remove from oven and rest for 3-5 minutes before serving.