After baking, potatoes Anna (aka pommes Anna) is crispy around the edges and tender in the middle. Perfect for slicing and serving with your choice of protein!
Thinly slice the potatoes. Heat the oven to 425°F. Using a mandoline or a food processor with a slicing blade, slice the potatoes as thinly as possible, ⅛- to ¼-inch thick or thinner. Do not rinse the sliced potatoes or place in water — the starch is needed to bond the layers.
Warm the skillet before adding potatoes. Add 1 tablespoon melted butter to a 10-inch well-seasoned cast-iron skillet over medium heat. Cook until the butter foams, then remove from the heat. Stir 1 teaspoon chopped thyme leaves into the remaining 3 tablespoons butter.
Arrange the layered potatoes in concentric circles. Working quickly while the pan is still warm, start in the center of the skillet to arrange potato slices in a circular pattern, slightly overlapping, to create one layer. Sprinkle with ¼ teaspoon Kosher salt and drizzle with 1 tablespoon butter mixture. Top with another layer of potatoes. Use your hands to gently press the potatoes into the pan. Sprinkle with ¼ teaspoon salt and drizzle with 1 tablespoon butter mixture. Repeat, pressing layers gently, until all potatoes and butter are used.
Bake the potatoes. Return the skillet to the stove over high heat until the butter in the pan sizzles, about 2 minutes. Spray a piece of foil with baking spray, cover the skillet, and transfer to the oven. Bake for 30 minutes covered with foil and 30 minutes uncovered until the potatoes are fork-tender.
Rest, slice, and serve. Let stand 10 minutes, then run a small spatula around the edge and bottom of the skillet to loosen. Turn out onto a cutting board or plate, and cut into wedges.