Sweet Potatoes Au Gratin is a delicious spin on a comfort food classic. This cheesy, hearty casserole is easy to prepare and makes for a perfect side dish.
If you are looking to mix things up at the dinner table, sweet potatoes au gratin is the perfect way! I’ve always loved sweet potatoes but I tend to only eat them in one of two ways; baked whole or in a sweet potato casserole.
I make Au Gratin Potatoes often, but it wasn’t until recently that I tried switching out russet potatoes for sweet potatoes. I have to say, I’m sure glad I gave this recipe a try. This dish is slightly sweet, savory, creamy, and incredibly cheesy.
While this recipe is great for any occasion, it really makes for a perfect holiday side dish. If you have a big menu to prepare and would like to make this ahead of time, you certainly can. Just assemble everything in your pan, cover it with foil, place it in the refrigerator, and wait until the next day to bake it.
Difference Between Scalloped Potatoes and Au Gratin Potatoes
You might be wondering what the difference is between au gratin and scalloped potatoes? Some people use these terms interchangeably as they are very similar but slightly different. Both are creamy casserole-like dishes made with potatoes.
Scalloped potatoes are made with a cream sauce but do not include any grated cheese. Au gratin potatoes are a bit more complex. The word gratin is French and means topped with a brown crust often using bread crumbs or cheese. Because you can never have enough cheese, we layered the cheese with the potatoes and added a final layer on top for the traditional au gratin touch.
How To Make Sweet Potatoes Au Gratin
Take a medium pot and combine the butter, heavy cream, minced garlic, salt, nutmeg, and cinnamon. Allow the ingredients to simmer for 10 minutes until it is slightly reduced and thickened. Turn off the heat and let it cool slightly. In a separate bowl, whisk the eggs. Pour the cream mixture through a fine mesh sieve, over the eggs, and whisk quickly to emulsify. Mix in the chopped fresh thyme.
Peel and slice 2-3 sweet potatoes into ⅛ inch thick rounds. A mandolin slicer is helpful when slicing the potatoes. It ensures each cut is the same thickness and it’s a time saver. If you don’t have a mandolin slicer, just try your best to cut each piece evenly.
Begin layering the sweet potatoes into a greased cast iron skillet. Slightly overlap your slices and drizzle ½ cup of the cream mixture over the first layer and top it with ½ cup of the shredded gruyere. Repeat this process again and then add the remaining cream mixture and gruyere cheese to the top of the sweet potatoes. Cover your pan with aluminum foil, but try to keep the foil from touching the top layer of cheese. Now you are ready to bake.
Baking the Au Gratin Sweet Potatoes
Here at the Grilling Guide, we like to cook anything we can on the grill, but this dish can also be prepared in an oven. Simply heat your grill or oven to 400°F and cook the sweet potatoes au gratin for 40 minutes. Then, remove the foil and continue to cook for an additional 20 minutes.
Once all of the potatoes are cooked through and soft remove from the grill or oven and allow to cool for about 10 minutes before serving.
Cooking Tips
- When adding the cream mixture to the eggs, add just a little bit at first and whisk with the eggs. This will help keep the eggs from scrambling and getting chunks of egg in your cream.
- I used 2 garlic cloves, but if you’re a garlic-lover, feel free to increase to 3-4 cloves.
- If you’re a cheese lover, you can easily increase the Gruyere to 8oz or 10oz. Simply increase the amount of cheese used in each layer.
- If you’re nervous about the foil sticking to the cheese, you can add the last layer of cheese once the skillet is uncovered and bakes for the last 20 minutes.
Other Side Dishes To Try
- Smoked Mac and Cheese
- Cheesy Foil Packet Potatoes
- Twice Baked Potatoes
- Stuffed Mushrooms
- Baked Beans
Sweet Potatoes Au Gratin
Ingredients
- 2 pounds sweet potatoes (about 2-3 large sweet potatoes) peeled and sliced into ⅛ inch rounds
- 2 tablespoons butter unsalted
- 2 cups heavy whipping cream
- 2 cloves garlic minced
- ¼ teaspoon fine sea salt
- ¼ teaspoon ground nutmeg
- ¼ teaspoon ground cinnamon
- 2 tablespoons fresh thyme chopped
- 2 large eggs at room temperature
- 6 ounces gruyere cheese shredded
Instructions
- Preheat the grill to 400°F and grease a 10.25” cast iron skillet with cooking spray.
- In a medium pot, combine the butter, heavy cream, minced garlic, salt, nutmeg, and cinnamon. Simmer for 10 minutes until slightly reduced and thickened. Turn off the heat and let it cool slightly.2 tablespoons butter, 2 cups heavy whipping cream, 2 cloves garlic, ¼ teaspoon fine sea salt, ¼ teaspoon ground nutmeg, ¼ teaspoon ground cinnamon
- In a large mixing bowl, add the eggs & whisk. Pour the warm cream mixture through a fine mesh sieve, over the eggs, and whisk quickly to emulsify. Mix in the chopped thyme.2 large eggs, 2 tablespoons fresh thyme
- Begin layering the gratin in the greased pan by placing a layer of slightly-overlapped sliced sweet potatoes. Drizzle ½ cup of the egg-cream mixture over the top of the potato layer and spread into an even layer & top with ½ cup shredded gruyere cheese.2 pounds sweet potatoes (about 2-3 large sweet potatoes), 6 ounces gruyere cheese
- Repeat the layering process with another layer of potatoes, ½ cup egg-cream mixture, ½ cup shredded gruyere. Then add the remaining potatoes, remaining egg cream mixture and remaining gruyere cheese.
- Cover the pan with aluminum foil (the top cheese layer shouldn’t touch the foil) and bake for 40 minutes. Then, uncover and bake uncovered for an additional 20 minutes.
- Allow to cool for 10 minutes before serving.
Notes
- When adding the cream mixture to the eggs, add just a little bit at first and whisk with the eggs. This will help keep the eggs from scrambling and getting chunks of egg in your cream.
- I used 2 garlic cloves, but if you’re a garlic-lover, feel free to increase to 3-4 cloves.
- If you’re a cheese lover, you can easily increase the Gruyere to 8oz or 10oz. Simply increase the amount of cheese used in each layer.
- If you’re nervous about the foil sticking to the cheese, you can add the last layer of cheese once the skillet is uncovered and bakes for the last 20 minutes.