• Heat oven to 425°. Place butter in a microwave-safe cup and melt in two 20 sec intervals. Stir until completely melted.

  • Brush a well-seasoned 10-inch cast-iron skillet liberally with some butter. Stir thyme into remaining butter.

  • Peel potatoes and cut in half crosswise. Set a mandoline slicer to 1/8-inch slices. Using the mandoline's hand guard, thinly slice potatoes.

  • Working quickly and starting in center of skillet, overlap slices in concentric circles to create 1 layer. Sprinkle with scant 1/4 tsp salt and drizzle with about 2 tsp butter mixture. Top with another layer of potatoes and use your hands to press gently; sprinkle with salt and drizzle with butter. Repeat, pressing layers gently, until all potatoes and butter are used. Coat a sheet of foil with baking spray and cover pan.

  • Bake 30 min covered with foil and 30 min uncovered. Let stand 10 min, then run a spatula around edge and under bottom. Turn out onto a cutting board.

Nutrition Facts

135 calories; 6 g total fat; 4 g saturated fat; 437 mg sodium. 20 g carbohydrates; 2 g fiber; 1 g sugar; 2 g protein;