Preheat oven to 350°F. Line a baking sheet with parchment paper.
Wash and scrub the potatoes and then dry them off with a towel. Then slice the potatoes in half.
In a large bowl, whisk together the butter, olive oil, garlic, red chili flakes, Pecorino Romano, salt and black pepper.
Then add the potatoes into the butter marinade and combine all the ingredients together. Make sure all sides of the potatoes are coated well with the marinade.
Spread the finely grated Parmesan onto the parchment paper. Then place the cut-side of the potatoes facing down on top of the grated Parmesan. Brush any leftover marinade on top of the potatoes.
Bake the potatoes for about 40-50 minutes until the tops of the potatoes and grated Parmesan become golden brown.