Preheat the oven to 425˚F. Using a small sharp knife, score the potatoes. Place the butter in an 9 x 13-inch baking dish and set in the oven for 5 minutes, until the butter is melted.
Remove the dish from the oven, add parmesan cheese and spices until well combined and they form a paste. Spread with a spatula to coat the bottom of the pan with the paste.
Place the halved potatoes cut side down in the baking dish. Brush with the reserved melted butter on top. Bake until golden brown and crispy, about 35 minutes.
Separate the potatoes and serve with a ranch dip, if desired.
Tip: Don't skip scoring the potatoes before roasting them for full flavor and texture. The cuts help get the parmesan butter paste deeper into the potatoes and give you that crispy, crunchy texture we all love!