Ingredients
1 1/4 pounds Yukon Gold potatoes (3 to 4 medium), peeled
1 1/4 pounds sweet potatoes (2 medium), peeled
6 tablespoons unsalted butter, melted
Coarse salt and freshly ground pepper
Preparation
Preheat oven to 425 degrees. Cut Yukon Gold and sweet potatoes into 1/8-inch-thick slices with a handheld slicer or sharp knife, keeping potato varieties separate.
Brush an ovenproof 9- or 10-inch nonstick skillet with some butter. Starting in center of pan, arrange about 20 Yukon Gold slices, slightly overlapping, in a circular pattern, covering surface. Brush with butter and generously season with salt and pepper. Make next layer with sweet-potato slices; brush with butter and season. Repeat, alternating colors. Drizzle remaining butter on top of potatoes.
Cook potatoes over medium-high heat until butter vigorously bubbles in pan, about 4 minutes. Transfer to oven and bake 30 minutes. Tent loosely with foil and continue to bake until potatoes are easily pierced with a knife, about 20 minutes more. Remove from oven, and run a heatproof flexible spatula around edges of potatoes to loosen. Let cool; carefully invert onto a plate, cut into wedges, and serve.
