Easy Sweet Potato Gratin is a simple, comforting dish featuring tender slices of sweet potatoes baked in a creamy sauce with a golden, cheesy crust on top. The natural sweetness of the potatoes pairs beautifully with the rich cheese, making every bite warm and satisfying. It’s a great way to bring some cozy flavors to your table without too much fuss.
I love making this gratin when I want something special but don’t have hours to spend in the kitchen. It’s really straightforward to put together—just layer the potatoes, pour over the creamy mixture, and let the oven do the work. One tip I like is to use a mix of cheeses for extra flavor and meltiness; it always makes the top just perfect and bubbly.
This dish is perfect as a side for holiday dinners or a cozy weeknight meal. I often serve it alongside roasted chicken or a fresh green salad to balance out the richness. Whenever I make it, it always gets compliments and usually disappears fast because it’s just that good. I find it’s a crowd-pleaser and a great way to enjoy sweet potatoes in a new way.
Key Ingredients & Substitutions
Sweet Potatoes: Thin slices help cook evenly and become tender. You can use Yukon Gold potatoes for a milder flavor or even mix sweet and regular potatoes.
Heavy Cream: This makes the gratin rich and creamy. If you want a lighter dish, try half-and-half or whole milk, but the sauce won’t be as thick.
Gruyère Cheese: Gruyère melts beautifully and adds a nutty taste. Swiss cheese works well too, and mozzarella can be added for extra meltiness.
Fresh Thyme & Nutmeg: Thyme gives a fresh herbal aroma, while nutmeg adds warmth. If you don’t have thyme, try rosemary or sage as tasty alternatives.
How Can I Ensure Evenly Cooked and Tender Sweet Potatoes in This Gratin?
Getting tender sweet potatoes is key to a great gratin. Here’s how to do it:
- Slice evenly: Use a mandoline or sharp knife to cut 1/8-inch thick slices so they cook at the same rate.
- Layer with care: Arrange slices in single, even layers to allow the cream and cheese to coat everything.
- Cover while baking: Start baking covered with foil to trap moisture, helping steam the potatoes through.
- Finish uncovered: Remove foil later to brown the cheese and develop that delicious crust.
- Check doneness: Pierce with a fork or knife; it should slide in easily but not mash the layers.
Patience is important—baking slow and steady makes the flavors blend and the textures perfect. I like to let it rest before serving so the layers set nicely and won’t fall apart on the plate.
Equipment You’ll Need
- Mandoline slicer – helps you get even, thin sweet potato slices that cook evenly.
- Medium saucepan – to gently warm the cream mixture and infuse it with garlic and herbs.
- Whisk – keeps the cream smooth and well mixed with seasonings.
- Medium baking dish (about 9×9 inches) – perfect size for layering and baking the gratin evenly.
- Aluminum foil – to cover the dish and trap moisture while baking.
Flavor Variations & Add-Ins
- Add cooked crumbled bacon or pancetta for a smoky, salty touch that pairs well with sweet potatoes.
- Mix in chopped fresh sage or rosemary instead of thyme for a woodsy herbal flavor.
- Stir in some shredded Parmesan with the Gruyère for a sharper, nuttier cheese crust.
- Include thinly sliced onions or leeks between layers for extra sweetness and texture.
Easy Sweet Potato Gratin
Ingredients You’ll Need:
For The Gratin:
- 3 large sweet potatoes, peeled and thinly sliced (about 1/8-inch thick)
- 1 1/2 cups heavy cream
- 1 garlic clove, minced
- 1 teaspoon fresh thyme leaves (plus extra for garnish)
- 1/4 teaspoon ground nutmeg
- Salt and freshly ground black pepper, to taste
- 1 1/2 cups shredded Gruyère cheese (or Swiss cheese)
- 2 tablespoons unsalted butter, softened (for greasing the baking dish)
How Much Time Will You Need?
Get ready to spend about 15 minutes preparing the ingredients and layering the gratin. The baking time is around 55-60 minutes, so from start to finish, count on about 1 hour and 15 minutes before this cheesy, creamy dish is ready to enjoy.
Step-by-Step Instructions:
1. Preparing to Bake:
First, preheat your oven to 375°F (190°C). Take your softened butter and lightly grease a medium baking dish to keep the gratin from sticking.
2. Making the Cream Mixture:
In a small saucepan over low heat, gently warm the heavy cream. Add in the minced garlic, fresh thyme leaves, ground nutmeg, salt, and pepper. Stir occasionally until the cream is hot and fragrant—be careful not to let it boil. Then, remove it from the heat and set it aside.
3. Layering the Gratin:
Arrange a single layer of the thinly sliced sweet potatoes evenly on the bottom of your prepared baking dish. Spoon some of the warm cream mixture over the potatoes, then sprinkle a portion of the shredded Gruyère cheese evenly on top. Repeat this layering process — potatoes, cream, cheese — until you have used all your ingredients. Make sure to finish with a nice layer of cheese on top.
4. Baking the Dish:
Cover your baking dish tightly with aluminum foil and place it in the oven. Bake for 30 minutes to give the potatoes time to soften. After 30 minutes, remove the foil and bake uncovered for another 25 to 30 minutes until the top turns a beautiful golden brown, bubbles with cheesy goodness, and the sweet potatoes are tender when pierced with a fork.
5. Resting and Serving:
Once baked, allow the gratin to rest for 5 to 10 minutes. This helps the layers set and makes it easier to serve. Garnish with a few fresh thyme leaves for a pop of color and fresh flavor. Serve warm and enjoy your delicious, comforting sweet potato gratin!
Can I Use Frozen Sweet Potato Slices for This Gratin?
Yes, you can! Just make sure to thaw them completely and pat them dry to remove excess moisture before layering. This helps prevent a watery gratin and ensures even cooking.
Can I Make the Sweet Potato Gratin Ahead of Time?
Absolutely! Assemble the gratin up to the baking step, cover tightly, and refrigerate for up to 24 hours. When ready, bake covered for 30 minutes, then uncover and finish baking as directed.
How Should I Store Leftovers?
Store any leftovers in an airtight container in the refrigerator for up to 3 days. Reheat gently in the oven at 350°F (175°C) until warmed through to keep that creamy texture.
What Can I Substitute for Gruyère Cheese?
If you don’t have Gruyère, Swiss cheese or a mild cheddar work well. For extra flavor, try mixing in some Parmesan or mozzarella with the Swiss cheese for a gooey, delicious crust.
