Sweet Potato Gratin – Thinly sliced sweet potatoes are baked with cream and covered in Parmesan cheese to make for a sweet and savory side dish perfect for the holdiays!
November is here, which means Thanksgiving is not too far away. As you start thinking about your menu for those holiday festivities, you gotta include this Sweet Potato Gratin. It’s a new take on the classic au gratin potatoes (or scalloped potatoes), made with sweet potatoes and a little maple sugar.
I particularly love this dish because it blends sweet and savory flavors together – the sweet potatoes are cooked in a sweet cream base and topped with a savory Parmesan cheese before baking to perfection. And the added texture from the sliced potatoes sets them apart from a sweet potato casserole. You just cannot go wrong with this side dish.
Here is my Sweet Potato Gratin!
Making the sweet potato gratin
Au gratin potatoes look fancy and complicated to make. But the reality is that they are even easier and quicker to make than mashed potatoes. Yes, it’s true! Let’s talk through the process so you can see for yourself.
Slicing the Potatoes
So step one is to slice the potatoes. I have always used a mandolin slicer to get perfectly even slices because I just can’t get them thin enough with a knife. I love this slicer because it is super easy to use AND clean. Check and check.
Assembling the casserole
A mixture of heavy cream, maple sugar, cinnamon, nutmeg, and salt are stirred together in a medium saucepan and then put over medium heat. Remove from heat once it starts to boil and slightly thicken.
I used maple sugar in this recipe because I had it leftover from another recipe. But you can easily swap it out for pure maple syrup.
Baking the casserole
The casserole is baked with aluminum foil on top to keep it from browning too soon. But make sure the foil is not too tight so that the steam can escape.
After 30 minutes, remove the foil and let the casserole bake for 15 more minutes or until the top gets nice and golden brown.
Remove from the oven and let it cool for 20 minutes before serving.
Tips & Tricks
- Use a mandolin slicer. This ensures the slices are even and makes slicing super fast. When using a mandolin slicer, be EXTREMELY careful! You want to use the provided holder for the potato so you don’t allow your fingers to get close to the blades. If your mandolin doesn’t have that holder, please, please use knife gloves.
- Symmetrical sweet potatoes. To make the slicing easier, try to find sweet potatoes that are uniform in size. Sweet potatoes can come in super wonky, uneven shapes but you’ll be able to find some symmetrical ones.
- Grated Parmesan. Make sure you are using grated Parmesan, not shredded. Shredded Parmesan is super dry and won’t melt together like grated Parmesan does. Therefore, you will get a whole bunch of crispy brown flakes of Parmesan on top of the potatoes that doesn’t look super pretty. But if presentation isn’t important to you, then don’t worry about it!
- Layer the potatoes evenly. To ensure an even look and bake, layers the potatoes evenly in the casserole dish. This means you need to take your time layering them instead of throwing them straight into the dish.
Sweet Potato Gratin
- 2 cups heavy cream
- ¼ cup maple sugar or maple syrup
- 1 teaspoon salt
- ¼ teaspoon ground nutmeg
- ½ teaspoon ground cinnamon
- 3 pounds sweet potatoes peeled and sliced into 1/8 inch slices
- 3 tablespoons Parmesan cheese grated
- Preheat oven to 400 degrees. Add heavy cream, maple sugar, salt, nutmeg, and cinnamon to a medium sauce pan. Heat over medium heat until it begins to boil and thicken slightly. Add sliced sweet potatoes to a large bowl and then add heated cream. Gently toss together.
- Grease a medium casserole dish or square baking pan. Gently layer in sweet potatoes, adding liquid to every few layers. Pour leftover liquid over the top. Sprinkle with Parmesan cheese. Cover dish with aluminum foil with a corner pulled back to vent the steam.
- Bake for 30 minutes in a preheated oven. Remove foil and bake until top begins to get super crispy and brown, about 15 more minutes.
- Remove from oven and let it sit to cool for about about 15-20 minutes. Serve warm.