Preheat your oven to 400°F (200°C). Rinse the thinly sliced potatoes under cold water to remove excess starch, then pat them dry. Toss the potato slices with olive oil, salt, pepper, garlic powder, paprika, rosemary, and half the melted butter until fully coated.

Arrange half of the seasoned potato slices in a single layer in a 9-inch pie pan. Sprinkle shredded sharp cheddar and Parmesan cheese generously across the potatoes, and fan out the remaining potato slices on top.

Drizzle the remaining melted butter over the top and gently fold and pinch the edges of the potatoes to form a slight crust.

Bake in the preheated oven for 30-40 minutes until the edges are golden and crispy. Check for doneness and adjust baking time if necessary.