There’s something undeniably comforting about a warm, creamy sweet potato gratin, especially on a crisp evening when the aroma of baked vegetables fills your kitchen. This dish is perfect for cozy family dinners, weekend gatherings, or any time you want to elevate your meal with a side that feels both indulgent and wholesome. The golden layers of tender sweet potatoes, enriched with creamy sauce and a hint of savory seasoning, make every bite a celebration of flavor and texture.
Inspired by the classic French gratin technique, this recipe transforms simple sweet potatoes into a luxurious dish that balances sweetness and creaminess without being overly heavy. Whether you’re introducing this to your family for the first time or revisiting a cherished tradition, this gratin is sure to become a favorite. Its rich, velvety layers are ideal for pairing with roasted meats, fresh salads, or even enjoying as a standalone vegetarian centerpiece.
The beauty of a sweet potato gratin lies not only in its flavor but also in its versatility. You can prepare it ahead of time for an easy weeknight dinner, or make it fresh to impress guests at a special occasion. The subtle nutty undertones of roasted sweet potatoes combined with the silky cream sauce create a dish that is both elegant and comforting, perfect for creating memorable meals that everyone will love.
Ingredients
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3 large sweet potatoes, peeled and thinly sliced
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1 ½ cups heavy cream
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1 cup whole milk
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3 cloves garlic, minced
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1 teaspoon fresh thyme leaves
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½ teaspoon nutmeg, freshly grated
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Salt and black pepper, to taste
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1 cup shredded Gruyère or sharp cheddar cheese
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¼ cup grated Parmesan cheese
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2 tablespoons unsalted butter, for greasing the dish
Optional for garnish:
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Fresh parsley, chopped
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Additional thyme sprigs
Directions
Preheat the Oven: Begin by preheating your oven to 375°F (190°C). This temperature is ideal for slowly baking the sweet potatoes while allowing the cream and cheese to meld into a rich, velvety sauce. While the oven is warming, prepare your baking dish. Grease a 9×13-inch dish generously with unsalted butter, making sure to cover every corner. This step ensures that the gratin doesn’t stick during baking and helps the edges develop a lightly golden, caramelized finish. If you prefer, you can also line the dish with parchment paper for easier cleanup, but butter alone will suffice and add extra richness to the final dish.
Prepare the Sweet Potatoes: Next, peel your sweet potatoes carefully. Using a sharp vegetable peeler, remove the skin in long, smooth strokes to reveal the bright orange flesh beneath. Slice the sweet potatoes into even rounds, about ⅛-inch thick. Consistent thickness is crucial to ensure that the layers cook uniformly, avoiding undercooked or overly soft sections. For best results, consider using a mandoline slicer; it allows you to create perfectly uniform slices quickly and safely. As you slice, place the rounds in a large bowl to keep them organized, and if you like, rinse briefly in cold water to remove excess starch—then pat dry with a clean kitchen towel.
Make the Cream Sauce: In a medium saucepan, combine the heavy cream and whole milk, stirring gently to combine. Add the minced garlic, fresh thyme leaves, and freshly grated nutmeg. Heating the cream mixture slowly over medium heat allows the flavors to meld and prevents scalding. Do not let the mixture boil; it should reach a gentle simmer, warm enough to release the aroma of garlic and thyme while infusing the cream with subtle spice. Season lightly with salt and freshly ground black pepper, tasting as you go. Stir occasionally to ensure even heat distribution and to prevent the milk from forming a skin or sticking to the bottom of the pan. The resulting cream sauce should be smooth, fragrant, and slightly thickened, ready to soak into the sweet potatoes.
Layer the Gratin: Now comes the fun part—assembling the gratin. Begin by placing a single layer of sweet potato slices at the bottom of the prepared baking dish. Slightly overlap each slice so that the potatoes fit snugly and create a visually appealing pattern. This layering technique also ensures that the cream can seep into every corner, coating each slice evenly. Pour a portion of the warm cream mixture over the first layer, just enough to lightly cover the potatoes. Sprinkle a modest amount of shredded Gruyère or sharp cheddar cheese on top of the cream. Repeat this process, alternating layers of sweet potatoes, cream, and cheese until all ingredients are used. The top layer should be generous with cheese, as it will form a beautiful golden crust during baking. Press down lightly on the layers to ensure everything fits compactly, but avoid squishing the slices completely—they should retain their shape.
Bake the Gratin: Cover the dish with aluminum foil and place it in the preheated oven. Baking with the foil on for the first 30 minutes helps trap steam, gently cooking the sweet potatoes and preventing the top from browning too quickly. After 30 minutes, carefully remove the foil. Continue baking for an additional 25–30 minutes, keeping a close eye on the gratin. The sweet potatoes should be fork-tender, and the cheese on top should be melted and starting to turn a rich, golden brown. If you prefer a more pronounced crust, switch the oven to broil for the last 2–3 minutes, but watch carefully to avoid burning. During baking, the cream sauce will thicken and bubble around the potatoes, creating that signature luscious texture that makes this gratin irresistible.
Rest Before Serving: Once baked, remove the gratin from the oven and allow it to rest for 10–15 minutes before serving. This step is crucial, as it allows the cream to set slightly and the flavors to meld. Resting makes slicing easier and prevents the dish from becoming runny on the plate. The aroma of garlic, thyme, and nutmeg will intensify during this time, filling your kitchen with a warm, inviting scent that signals the dish is ready to enjoy.
Garnish and Serve: Just before serving, sprinkle freshly chopped parsley and a few thyme sprigs over the top to add a pop of color and an extra layer of fragrance. These fresh herbs complement the richness of the gratin and create an inviting presentation. Serve the creamy sweet potato gratin warm alongside roasted vegetables, a fresh salad, or your favorite main course. It also works beautifully as a standalone vegetarian dish, satisfying both comfort and elegance. For a family dinner, this gratin is sure to impress without requiring complicated techniques or rare ingredients, offering a perfect balance of creamy, cheesy, and subtly sweet flavors in every bite.
Prep Time, Cook Time, Total Time, Yield
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Prep Time: 20 minutes
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Cook Time: 55–60 minutes
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Total Time: 1 hour 15–20 minutes
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Yield: 6–8 servings
Notes
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Cheese Variations: Gruyère provides a smooth, nutty flavor, but sharp cheddar works equally well for a more pronounced taste. Mixing both cheeses creates a layered depth of flavor.
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Cream Substitutes: For a lighter option, substitute half of the heavy cream with whole milk or unsweetened plant-based milk. The texture may be slightly less rich but still delicious.
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Make-Ahead Option: You can assemble the gratin a day ahead and refrigerate it. Bake it covered for an additional 10–15 minutes to ensure thorough heating.
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Thinner Slices: Slicing the sweet potatoes thinner will reduce the baking time slightly and create a more delicate texture.
Tips for Perfect Sweet Potato Gratin
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Even Slices: Consistent thickness ensures that each layer cooks evenly. A mandoline slicer is recommended for precision.
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Cream Absorption: Allow the cream mixture to sit over the potato layers for a few minutes before baking. This helps the potatoes absorb more flavor.
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Golden Crust: For a more pronounced crust, broil the gratin for 2–3 minutes after baking, watching closely to prevent burning.
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Season in Layers: Lightly season each potato layer to distribute flavor evenly throughout the gratin.
Variations to Try
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Herbed Sweet Potato Gratin: Add fresh rosemary or sage to the cream mixture for an earthy twist.
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Spicy Sweet Potato Gratin: Include a pinch of cayenne pepper or smoked paprika for subtle heat.
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Nutty Crunch: Sprinkle chopped walnuts or pecans over the top before baking for a crunchy texture.
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Vegetable Medley: Mix in thin slices of carrots or parsnips for a colorful, nutrient-rich variation.
Why This Recipe Works
Creamy Sweet Potato Gratin combines simple ingredients with classic techniques to create a dish that feels luxurious yet approachable. The careful layering of potatoes and cream ensures every bite is tender and flavorful, while the melted cheese adds richness and depth. This recipe is forgiving, allowing cooks of all skill levels to achieve a professional-tasting gratin without stress.
The balance of sweetness from the potatoes, creaminess from the sauce, and savoriness from the cheese makes it universally appealing. It’s a dish that invites creativity, from changing the herbs to experimenting with cheese blends. Each time you prepare it, you can customize it slightly to match the season, your pantry, or the occasion.
Making It Ahead for Holidays or Gatherings
One of the best things about this gratin is its make-ahead flexibility. You can assemble the dish a day in advance and refrigerate it. When ready to serve, simply bake it as directed, adding a few extra minutes if necessary. This makes it ideal for holiday meals or dinner parties when you want to minimize last-minute kitchen stress.
Frequently Asked Questions
Can I use canned sweet potatoes?
While fresh sweet potatoes yield the best texture and flavor, you can use canned sweet potatoes in a pinch. Be sure to drain them thoroughly and slice them evenly before layering. You may need to adjust baking time slightly, as canned sweet potatoes are softer.
What can I serve with sweet potato gratin?
This gratin pairs wonderfully with roasted chicken, turkey, or beef. It’s also perfect alongside a fresh green salad or steamed vegetables for a lighter meal.
Can I make it vegan or dairy-free?
Yes! Substitute heavy cream and milk with coconut milk or cashew cream, and use vegan cheese alternatives. The flavor will be slightly different but still rich and satisfying.
How do I store leftovers?
Leftovers can be stored in an airtight container in the refrigerator for up to 3 days. Reheat in the oven at 350°F (175°C) until warmed through to maintain the creamy texture.
Creamy Sweet Potato Gratin Recipe
- Total Time: 1 hour 15–20 minutes
- Yield: 6–8 servings 1x
Description
A warm, indulgent side dish perfect for cozy dinners or special occasions. This gratin layers tender sweet potatoes with a creamy, flavorful sauce and melted cheese, creating a comforting dish that everyone will love. Its golden top and rich interior make it as beautiful as it is delicious.
Ingredients
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3 large sweet potatoes, peeled and thinly sliced
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1 ½ cups heavy cream
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1 cup whole milk
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3 cloves garlic, minced
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1 teaspoon fresh thyme leaves
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½ teaspoon nutmeg, freshly grated
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Salt and black pepper, to taste
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1 cup shredded Gruyère or sharp cheddar cheese
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¼ cup grated Parmesan cheese
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2 tablespoons unsalted butter, for greasing the dish
Optional for garnish: -
Fresh parsley, chopped
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Additional thyme sprigs
Instructions
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Preheat your oven to 375°F (190°C). Grease a 9×13-inch baking dish with butter to prevent sticking and help the gratin brown evenly.
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Peel and slice the sweet potatoes into ⅛-inch-thick rounds. Use a mandoline slicer for uniform slices if available.
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In a medium saucepan, combine heavy cream, milk, minced garlic, thyme, and nutmeg. Heat over medium heat until warm but not boiling. Season with salt and black pepper.
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Arrange a layer of sweet potato slices at the bottom of the prepared dish, slightly overlapping. Pour a portion of the cream mixture over the layer and sprinkle with a small amount of shredded cheese.
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Repeat layering until all sweet potatoes, cream, and cheese are used, finishing with a generous layer of cheese on top.
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Cover the dish with aluminum foil and bake for 30 minutes. Remove the foil and bake for an additional 25–30 minutes, until potatoes are tender and the top is golden brown.
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Allow the gratin to rest for 10–15 minutes before serving to let the cream set.
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Garnish with chopped parsley and thyme sprigs. Serve warm alongside your favorite main dish or as a hearty vegetarian option.
Notes
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Use a combination of Gruyère and cheddar for a richer flavor.
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Plant-based milk and vegan cheese can be used for a dairy-free version.
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Slice sweet potatoes thinly and evenly for uniform cooking.
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Assemble ahead of time and refrigerate; bake before serving, adding 10–15 minutes if chilled.
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Broil for 2–3 minutes at the end for a crispier top, watching closely to avoid burning.
- Prep Time: 20 minutes
- Cook Time: 55–60 minutes
