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This simple sweet potato gratin features thinly sliced sweet potatoes layered with Gruyère and fresh thyme, creating a perfectly buttery, cheesy dish. Made without milk or cream, it’s slightly lower in calories yet still incredibly rich, decadent, and delicious. You are going to love it!
Sweet potato gratin has been a staple on our family’s holiday table for years, and this updated version might be the best yet. Made with just a few simple ingredients like sweet potatoes, Gruyère, and thyme. The gratin bakes up beautifully, and the leftovers are even better.
This gratin recipe with sweet potatoes is so easy to make but is such an impressive and delicious dish everyone will go crazy for!
You may also love these mashed sweet potatoes, sweet potato casserole or instant pot sweet potatoes.
This recipe was adapted from Skinnytaste’s version that we have been making for years!
Why you’ll love this sweet potato gratin recipe
- No cream or milk – this lightened up au gratin with sweet potatoes is still creamy and buttery with no milk or cream.
- Easy to make – Just a few easy steps and ingredients are needed to make this simple sweet potato recipe.
- Perfect side dish – cheesy potatoes, especially with sweet potatoes make a wonderful side dish that goes with so many things.
Jump to:
- Why you’ll love this sweet potato gratin recipe
- Ingredients and Substitutions for Sweet Potato Au Gratin
- Recommended Kitchen Tools
- How To Make Sweet Potato Gratin
- Recipe variations
- What to serve with sweet potato au gratin?
- Make it ahead
- Storing and Reheating Gratin
- FAQs
- More Healthy Sweet Potato Recipes
- Sweet Potato Gratin
Ingredients and Substitutions for Sweet Potato Au Gratin
Here is the list of ingredients you’ll need to make this simple sweet potato gratin recipe. Get the complete list of recipe ingredients, instructions and nutrition in the recipe card at the bottom of this post.
- Sweet potatoes – 5-6 medium sweet potatoes (about 2 lbs) that are even in size for nice beautiful thin even slices, about ⅛ inch in thickness.
- Cheese – I used a combination of fresh grated gruyere cheese and parmesan cheese for the perfect combination of savory and salty flavors.
- Butter – is used to coat the potatoes to give them that nice buttery flavor.
- Thyme – fresh thyme is an essential ingredient in any potato recipe since it pairs so well with potatoes, especially sweet potatoes.
- Seasoning – salt, pepper and garlic powder add a wonderful layer of seasoning that helps enhance all of the other ingredients.
Recommended Kitchen Tools
- Mandolin slicer
- Mixing bowls
- Baking dish
How To Make Sweet Potato Gratin
Here is a summary with step-by-step photos for how to make this homemade sweet potato gratin recipe.
- Peel the sweet potatoes then use a mandolin slicer to thinly slice the sweet potatoes about ⅛ inch thick.
- Add the sliced sweet potatoes to a mixing bowl and toss them with the melted butter, thyme and seasoning.
- Layer the sweet potatoes and cheese in a prepared baking dish. I used a 3 quart gratin dish.
- Top with the remaining cheese, cover with foil and bake for 30 minutes in a preheated oven. Remove the foil and bake 10-15 more minutes until golden and bubbly.
Recipe variations
- Switch up the cheeses by using sharp cheddar or a sweeter cheese instead of Gruyère, or try Pecorino Romano in place of Parmesan.
- Substitute Yukon gold or russet potatoes for the sweet potatoes.
- Add variety by using herbs like sage or rosemary along with the thyme for a more aromatic au gratin.
- Make individual mini au gratins using small gratin dishes: divide the ingredients among 6 dishes, bake covered for about 20 minutes, then uncover and bake 5–7 minutes more. Place the dishes on a baking sheet for easier handling.
What to serve with sweet potato au gratin?
We love this au gratin for the holidays served with turkey or ham, brussels sprouts salad and homemade biscuits. You can also make it for a weeknight or weekend meal and serve it with pork tenderloin or chicken.
Make it ahead
To make this sweet potato au gratin ahead, assemble and bake it without adding the final layer of cheese. Let it cool completely, cover, and refrigerate overnight; the next day, top with the remaining cheese and bake until heated through and nicely melted.
Storing and Reheating Gratin
Homemade potato gratin will keep in an airtight container in the refrigerator for up to 4 days. Reheat individual portions in the microwave until warmed through.
FAQs
Although peeling the sweet potatoes isn’t necessary, it definitely makes them easier to slice and enjoy in the gratin
Yes you can, yukon gold potatoes or russets will also work. Just peel them before you slice and layer them.
Scalloped potatoes are typically baked in a creamy milk or cream sauce without cheese. Potatoes au gratin include cheese layered throughout or on top, giving the dish a browned, crispy crust.
Sweet potatoes pair well with cheeses that balance their natural sweetness, such as tangy goat cheese, salty feta, nutty Parmesan, sharp cheddar, and mildly sweet, melty Gruyère.
More healthy sweet potato recipes
More Healthy Sweet Potato Recipes
Looking for other recipes like this? Try these:
Did you try this sweet potato au gratin recipe? If you did, then please leave a rating and comment below. I would love to hear how yours turned out!
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Sweet Potato Gratin
- Total Time: 60 minutes
- Yield: 10–12 servings 1x
- Diet: Gluten Free
Description
This simple sweet potato gratin features thinly sliced sweet potatoes layered with gruyere cheese and fresh thyme, creating a perfectly buttery, cheesy dish. Made without milk or cream, it’s slightly lower in calories than traditional gratin yet still decadent, golden and delicious!
Ingredients
- 5 medium sweet potatoes – about 2 lbs
- 2 tablespoons butter – melted
- 1 cup grated gruyere cheese
- ⅔ cup grated parmesan cheese
- 1.5 tablespoons fresh thyme – plus more for serving
- 1 teaspoon kosher salt
- ½ teaspoon ground black pepper
- ½ teaspoon garlic powder
Instructions
- Preheat the oven to 425 °F and spray or butter a 3 quart gratin dish or 9×13 baking dish with oil or butter to prevent sticking.
- Wash and dry the sweet potatoes really well then peel them using a vegetable peeler and discard the peels. Use a mandolin slicer to slice them into thin slices that are about ⅛ inch thick.
- Place the sliced potatoes into a large mixing bowl and toss them with the melted butter, thyme, salt, pepper and garlic powder. Make sure to get them all nice and coated.
- Then layer ⅓ of the sliced potatoes in the bottom of the prepared pan layering them to allow some to overlap. Then sprinkle on about ⅓ of the cheese in an even layer. I like to mix the two cheese together before I layer them. Press down on the potatoes to they are nice and snug then continue until you have three layers, topping the final layer with the remaining cheeses.
- Cover the au gratin with foil, but spray the foil with olive oil spray to prevent sticking and place the coated side of the foil over the potatoes. Bake on the middle rack of the oven for 30 minutes.
- Then remove the foil, place the gratin on the top rack of the oven and baked for 10-15 more minutes until it is golden and bubbly.
- Remove, allow to cool for a few minutes and serve!
Notes
- Use any potatoes like sweet potatoes, Yukon gold or russets in this recipe.
- Store leftovers in an airtight container in the refrigerator for up to 4 days.
- Reheat leftovers in the microwave until fully heated through and the cheese is re-melted.
- See post for make ahead instructions.
- Prep Time: 15 minutes
- Cook Time: 45 minutes
- Category: Healthy Side Dishes
- Method: Oven
- Cuisine: American
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