- 2 medium sweet potatoes (1 pound), peeled
- 2 medium russet potatoes (1 pound), peeled
- 2 cloves garlic, crushed
- 2 teaspoons fresh thyme leaves
- kosher salt and black pepper
- 2 1/2 cups heavy cream
- butter, for the foil
- Heat oven to 400° F. In a food processor fitted with the thinnest (2-millimeter) slicing disk, slice the potatoes.
- In a shallow 1½-quart baking dish, toss the potatoes, garlic, thyme, ¾ teaspoon salt, and ¼ teaspoon pepper. Add the cream and press gently to submerge the potatoes.
- Cover the dish with buttered foil, place on a rimmed baking sheet, and bake for 20 minutes. Remove the foil and bake until the potatoes are tender and the top is golden brown, 25 to 30 minutes more.