Add olive oil to a large skillet and bring to medium heat.
Quarter mushrooms and add to skillet with salt and pepper to taste. Saute until mushrooms have softened and most of the water has cooked off, approximately 7-9 minutes.
Add garlic to skillet and cook until fragrant, approximately 1 minute.
Stir in cubed cream cheese until mushrooms are evenly coated.
Remove skillet from heat and mix in mozzarella, ½ C. panko, and ¼ parmesan.
Once combined, transfer mixture to a greased 8×8 baking dish.
In a small bowl, combine parsley, melted butter, remaining cheese, and panko. Sprinkle mixture on top of the mushrooms.