Stacked Sweet Potato Gratin Muffin Tin Rounds
Thin sweet potato slices tossed in garlic thyme cream, stacked in a muffin tin with Gruyere, and baked until the tops frizzle and brown. A savory side dish in twelve neat individual portions.
Servings 12 rounds
Ingredients
For the Stacks
- 2.5 lb sweet potatoes narrow, about 2 to 2.5 inches across, peeled
- ¾ cup heavy cream
- 2 large cloves garlic finely grated
- 1 tablespoon fresh thyme leaves
- 1 ¼ teaspoons fine salt
- ½ teaspoon black pepper freshly cracked
- 4 oz Gruyere coarsely grated
- ⅓ cup Parmesan finely grated
- 2 tablespoons unsalted butter softened, for the muffin tin
Instructions
Slice and Season
- Peel the sweet potatoes and slice them into rounds about ⅛ inch thick, using a mandoline with the hand guard or a sharp knife. Keep the thickness consistent.
- Heat the cream in a small pan until it steams gently, then remove from the heat and stir in the grated garlic, thyme leaves, salt, and pepper. Let it infuse for 5 minutes.
- Put the sliced rounds in a large bowl, pour the warm cream over, and toss with your hands until every slice is coated on both faces, separating any that stuck together.
Build the Stacks
- Heat the oven to 375 degrees F and butter a 12 cup muffin tin thoroughly, bottom and sides.
- Stack 8 to 10 slices in each cup, largest rounds at the bottom and smallest at the top, sprinkling a pinch of grated Gruyere after the third slice and again after the sixth.
- Build each stack slightly above the rim of the cup, since they settle by about a third as they bake. Spoon any remaining cream over the tops, divided between the cups.
Bake and Release
- Cover the tin loosely with foil and bake for 25 minutes.
- Remove the foil, scatter the Parmesan over the tops, and bake uncovered another 20 to 25 minutes, until the top slices are curled and browned at their edges and a paring knife slides into the center of a stack with no resistance.
- Rest the tin 5 minutes, run a thin paring knife around each cup, and lift the rounds out with a small offset spatula. Serve right side up.
Notes
- Buy narrow potatoes: rounds from a potato 2 to 2.5 inches across drop straight into a standard muffin cup with no trimming.
- The foil is not optional: the covered phase steams the interior tender, the uncovered phase frizzles the top. Skip it and you get browned tops over firm centers.
- Do not flood the cups: cream should reach about two thirds of the stack height. Any more and the tops never dry out and crisp.
- Make ahead: hold sliced potatoes in the cream up to 24 hours, or build the tin and refrigerate up to 4 hours, adding 8 minutes to the covered bake.
- Savory only: there is no sugar, maple, or honey in this recipe, and adding any fights the Gruyere.