- 4 lbs. russet potatoes peeled
- 3 tablespoons extra-virgin olive oil
- 3 tablespoons unsalted butter melted
- 4 shallots peeled and thickly sliced lengthwise
- 1 teaspoon red pepper flakes
- Coarse salt and ground black pepper
- 8 sprigs thyme
- Heat oven to 400 degrees. In a small bowl, combine butter and oil. Brush the bottom of a round 9-inch baking dish with butter mixture. Using a mandolin, slice potatoes crosswise very thinly.
- Arrange potatoes thin sides up in dish slightly fanning out slices as you go. Wedge shallot slices sporadically throughout. Sprinkle pepper flakes over potatoes, season generously with salt and 1/4 teaspoon pepper and brush with remaining butter mixture. Roast until potatoes are cooked through, with a golden-crisp crust, about 1 hour. Tuck remaining thyme around potatoes and bake for 15 minutes more.