Place skin and fat in a small saucepan. Heat over medium heat, and cook until the fat has rendered. Remove from heat, and set aside.
Preheat oven to 450 degrees. Bring a medium saucepan of water to a boil. Add a large pinch of salt and potatoes. Cook for 3 minutes. Drain well.
Place a small rimmed baking sheet in the oven until hot. Remove, and pour about 2 tablespoons of the rendered fat onto the baking sheet to coat. Place potatoes, cut-side down, on baking sheet. Season with salt and pepper. Roast until golden brown and tender, about 25 minutes. Remove from oven, and season with salt and pepper; serve immediately.