Sweet Potato Gratin with Smoked Gouda and Rosemary

Sweet Potato Gratin with Smoked Gouda and Rosemary

Thin sweet potato slices bake in garlic-rosemary cream with smoked Gouda between the layers and a golden, melted cheese topping. Covering the dish for the first part of the bake gives the center time to soften before the topping browns. Because slice thickness and dish depth affect the timing, check the center with a thin knife rather than relying on the clock. After a short rest, serve the creamy gratin directly from its baking dish.

Ingredients for Sweet Potato Gratin

• 2 1/2 pounds sweet potatoes, peeled (about 1.15 kg)
• 1 1/2 cups heavy cream (350g)
• 8 ounces smoked Gouda, shredded (225g), divided
• 1 tablespoon unsalted butter, for the baking dish
• 2 cloves garlic, finely grated or minced
• 1 tablespoon finely chopped fresh rosemary, divided
• 1 teaspoon kosher salt, or to taste
• 1/2 teaspoon black pepper

Smoked Gouda varies in saltiness, so measure the salt rather than adding extra between the layers. Regular Gouda can replace it, though the gratin will be less smoky.

How to Make Sweet Potato Gratin

1. Prepare the dish and potatoes: Heat the oven to 375°F (190°C). Lightly butter a shallow 2-quart oval or 9-by-9-inch baking dish. Slice the peeled sweet potatoes evenly, about 1/8 inch thick.
2. Warm the cream: In a small saucepan over low heat, warm the cream with the garlic, about half the rosemary, the salt, and the pepper for 3 to 5 minutes. Remove from the heat when steaming and fragrant; do not let it boil.
3. Layer the gratin: Arrange the sweet potato slices in overlapping layers, scattering about 6 ounces of Gouda between them. Reserve the remaining 2 ounces for the topping. Pour the warm cream evenly over the potatoes; it should come partway up the layers, not cover them completely. Cover the dish tightly with foil.
4. Bake covered: Place the dish on the center rack and bake for about 35 to 40 minutes. The edges may begin to bubble before the center is tender.
5. Finish uncovered: Carefully remove the foil. Scatter the reserved Gouda and remaining rosemary over the top, then bake uncovered for about 20 to 25 minutes. Begin checking the center after about 50 minutes of total baking time. Rotate the dish once during this stage if the top browns unevenly.
6. Check and rest: The gratin is done when a thin knife slides into the center with little resistance, the cream bubbles at the edges, and the cheese has scattered golden-brown patches. If the center is firm, bake in 5-minute increments; cover the dish again if the cheese is getting too dark. Let the gratin rest for about 15 minutes before serving from the dish.

Why Slice Thickness and Dish Depth Matter

Keep the slices close to 1/8 inch thick so they cook at a similar rate. A mandoline can help; use its hand guard. Thicker slices or a deeper dish may need more baking time. Bubbling edges and browned cheese do not mean the center is tender, so use the knife check before taking the gratin out of the oven.

Serving and Storing Sweet Potato Gratin

Serve warm, scooping portions directly from the baking dish. For another layered sweet potato side, try Garlic-Herb Sweet Potato Stacks with Parmesan.

Refrigerate leftovers promptly in a covered container and use within 3 to 4 days. Reheat covered in a 325°F (165°C) oven until hot throughout; uncover briefly if the cheese topping needs refreshing. The gratin can be assembled shortly before baking, but do not leave the cream-and-potato dish at room temperature for an extended period. Freezing is not recommended because the creamy texture may change.

Nutrition

Approximate nutrition per serving, based on 1/8 of the gratin: 390 calories, 10g protein, 25g fat, and 31g carbohydrates. Per 100g: about 195 calories, 5g protein, 13g fat, and 16g carbohydrates. Values vary with ingredients and portion size.