Preheat oven to 375° and line a large baking sheet with parchment paper.

Make small slits in each potato, like an accordion, making sure not to cut all the way through. Place potatoes on a large sheet pan.

In a small bowl, whisk together melted butter, olive oil, and garlic. Brush mixture over potatoes then season with salt and pepper. Bake for 20 minutes, until the slits are starting to separate and the potatoes are beginning to turn golden.

Brush the potatoes with more of the melted butter mixture then sprinkle mozzarella and Parmesan on top. Bake for another 23 to 25 minutes, or until the potatoes are crispy on the outside and tender on the inside.

Garnish with parsley and serve warm.