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Creamy Spiraled Sweet Potato Gratin
Rich, bubbling cream and a golden parmesan crust turn humble sweet potatoes into a stunning centerpiece. You'll arrange thinly sliced potatoes vertically in a cast-iron skillet, creating a beautiful spiraled pattern that looks far more complicated than it actually is. The secret is steeping the heavy cream with crushed garlic and fresh thyme first, which infuses the entire dish with deep, savory flavor. It's a comforting, show-stopping side that pairs beautifully with roasted meats or stands proudly on its own.
Ingredients
- 1 Tbsp. unsalted butter, softened
- 5 medium sweet potatoes, peeled
- 1½ cups heavy whipping cream
- 4 garlic cloves, crushed
- 1 Tbsp. fresh thyme leaves, plus more for garnish
- ¼ tsp. black pepper
- 3 tsp. kosher salt, divided
- 2 oz. Parmesan cheese, finely grated (about ½ cup)
Instructions
- 1Preheat the oven to 350°F. Grease the bottom of a 10-inch cast-iron skillet or baking dish with the softened butter. Peel and thinly slice the sweet potatoes using a mandoline, aiming for about 1/16 inch thick.
- 2Arrange the potato slices vertically on their edges in the prepared skillet, fanning them out slightly to form a tight spiral pattern. Packing them tightly ensures they hold their shape while baking.
- 3Combine the heavy cream, crushed garlic cloves, fresh thyme leaves, black pepper, and 2 teaspoons of the kosher salt in a medium saucepan. Bring the mixture to a boil over medium heat.
- 4Lower the heat to medium-low and simmer for about 15 minutes, stirring frequently until the garlic softens. Discard the garlic cloves now if you prefer a milder flavor, or leave them in. Pour the infused cream evenly over the arranged sweet potatoes.
- 5Season the dish with the remaining 1 teaspoon of kosher salt and sprinkle the finely grated Parmesan cheese over the top. Cover the skillet tightly with aluminum foil.
- 6Bake for 50 to 55 minutes, until the sweet potatoes are tender when pierced with a knife. Remove the foil and continue baking for another 15 minutes so the top can brown.
- 7Take the skillet out of the oven and let the gratin rest for 10 minutes. This resting period helps the cream sauce thicken and set. Garnish with fresh thyme leaves before serving.
Notes
- Equipment: If you don't have a mandoline, use a sharp chef's knife to slice the sweet potatoes as thinly as possible, aiming for about 1/8 inch thick.
- Storage: Keep leftovers in an airtight container in the fridge for up to 4 days. Reheat gently in the oven or microwave.
- Flavor swap: Try adding a pinch of nutmeg to the cream mixture, or swap the fresh thyme for fresh rosemary.