This Sweet Potato Au Gratin is a stunning savory sweet potato dish with a creamy herb and cheese-flavored sauce and a deliciously crunchy bread crumb topping. It’s a perfect holiday dinner side dish for Thanksgiving and Christmas and pairs beautifully with chicken, turkey, ham, or a roast. This is a fun and elevated alternative to a sweet potato casserole.
Looking for more tasty potato side dishes? Try this delectable Potato Leek Gratin, these Garlic Herb Smoked Potatoes, or our Sweet Potato Soup. Or how about another gorgeous fall dish with our Hasselback Butternut Squash.
I love it when I can serve a dish that looks and tastes spectacular but is actually easy to make – it’s the best recipe combination! This Sweet Potato Au Gratin fits the bill perfectly. The thinly sliced sweet potatoes, made simply with a mandolin, make this side dish look far more complicated than it actually is.
When plated, a serving of this sweet potato gratin looks like something that could be served at a fancy restaurant, which makes it even more fun to serve at home. You’re going to have fun with this one!
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Adjustable Mandoline Food Slicer for Kitchen
What is the difference between scalloped and gratin potatoes?
The difference between Scalloped Potatoes and Au Gratin Potatoes is that Au Gratin Potatoes contain cheese, and Scalloped Potatoes do not. Generally, both types of potato dishes have a creamy base and are prepared similarly. The French phrase “Au Gratin” actually translates to “by grating,” referring to both the cheese as well as a crunchy bread crumb topping.
People have also asked if you can make scalloped sweet potatoes, and the answer is absolutely yes!! Let us show you how!!
What is in Sweet Potatoes Au Gratin?
Sweet Potatoes Au Gratin pack a big flavor punch, but they don’t require a lot of ingredients. Here’s what you’ll need:
Sweet Potatoes – To make the process of layering the thinly sliced potatoes a little simpler, look for sweet potatoes that are similar in size and shape. You’ll want about 4 or 5 medium size sweet potatoes.
Heavy Cream – This is the base for the cream sauce.
Eggs – These help thicken and bind the cream sauce.
Fresh Sage and Fresh Rosemary – These chopped herbs flavor the cream sauce and pair perfectly with the sweetness of the potatoes. If possible, use fresh herbs, not dried, for the best flavor profile.
Nutmeg – This helps bring out the rich flavors in the sweet potatoes.
Garlic – This adds a depth of flavor to the cream sauce that takes it to the next level.
Parmesan Cheese – Look for a block of aged Parmesan that you can grate yourself for this recipe. If you want a cheesier gratin, substitute Fontina or Gruyere for the Parmesan.
Panko Bread Crumbs – Use these plain bread crumbs to add a delicious crunch to the gratin.
Olive Oil – Use your best-tasting olive oil with the bread crumbs to add flavor and help them brown.
Paprika, Garlic Powder, Onion Powder, Cayenne – Add these flavorful ground spices to the bread crumb topping for a burst of flavor in every bite.
How to Make Sweet Potato Au Gratin
First, preheat oven to 400 degrees Fahrenheit. Peel the sweet potatoes. Then, using a mandolin or a sharp knife, thinly slice the potatoes into rounds about 1/8 inch thick.
Generously butter a gratin dish or a casserole dish (about 9×13). Sprinkle the bottom with a couple of tablespoons of grated Parmesan cheese. Place one layer of potatoes (use 1/3 of the potato slices) in the prepared dish, overlapping slightly as you layer them. Sprinkle with 1/4 teaspoon salt and a few grinds of black pepper.
In a medium saucepan, combine the heavy cream, chopped sage and rosemary, minced garlic, nutmeg, and a generous pinch of salt. Bring the cream mixture to a low boil over medium heat, then reduce heat to low and maintain a simmer. Simmer for about 10 minutes or until the mixture has reduced by 1/4.
Add the eggs to a medium bowl and whisk until lightly beaten. Slowly pour the hot cream mixture, while whisking continuously, into the eggs.
Pour 1/3 of the cream and egg mixture over the first layer of potatoes in the prepared dish (about 2/3 cup). Sprinkle with 1/3 cup of Parmesan cheese, then add the next layer of potato slices and repeat twice (three total layers of potatoes).
Now to Bake The Potatoes
After adding the final layer of cream and cheese, cover the baking dish with foil. Bake covered for 40 minutes or until the potatoes are tender.
While the potatoes are baking, combine the Panko Bread Crumbs, remaining Parmesan cheese, Paprika, Garlic Powder, Onion Powder, pinch of Cayenne, and olive oil in a medium bowl.
After the potatoes have been baked for 40 minutes, remove the foil. Carefully spread the breadcrumb mixture over the top of the potatoes and return to the oven. Bake uncovered for 20 to 25 minutes or until the bread crumbs are browned and the mixture is bubbling.
Recipe Pro Tips!
What is the Difference Between a Sweet Potato and a Yam?
This has been confusing, at the very least, as grocery stores and recipes call these one and the same, but they are very different vegetables and not even from the same group of vegetables.
Yams are lighter in color, like the shade of a potato. They are less sweet, starchier, and dryer. They are from the lily family of vegetables like onions, garlic, and asparagus.
Sweet potatoes actually have more nutritional value as they are higher in vitamin C, vitamin A, fiber, and protein. They also boost to have fewer calories too. They have a lovely orange color and are much tastier. Sweet Potatoes are from the Morning Glory family.
A famous recipe that circulates, and we have a link to below, is for Candied Yams, but they are actually Sweet Potatoes, hence the whole confusion.
LOVE SWEET POTATOES? WANT MORE?
We love sweet potatoes, too, and have these other recipes that you can enjoy!! Our crowning glory is this first recipe for Ruth’s Chris Copycat Sweet Potato Casserole, one if not the most popular recipes, especially for the holidays.
Sweet Potato Au Gratin
Ingredients
- 3 pounds sweet potatoes about 4 or 5
- 1 1/3 cup grated Parmesan cheese divided
- 2 cups heavy cream
- 3 tablespoons fresh sage chopped
- 1 tablespoon fresh rosemary chopped
- 3 garlic cloves minced
- pinch of ground nutmeg
- Salt and Pepper
- 1 cup panko breadcrumbs
- 1/2 teaspoon paprika
- 1/4 teaspoon onion powder
- 1/4 teaspoon garlic powder
- pinch of cayenne
- pinch of salt
- 2 tablespoons olive oil
- Butter for greasing casserole dish
Instructions
- Preheat oven to 400 degrees Fahrenheit. Peel the sweet potatoes. Then, using a mandolin or a sharp knife, thinly slice the potatoes into rounds, about 1/8 inch thick.
- Generously butter a gratin dish, or a casserole dish (about 9×13). Sprinkle the bottom with a couple of tablespoons of grated Parmesan cheese. Place one layer of potatoes (use 1/3 of the potato slices) in the prepared dish, overlapping slightly as you layer them. Sprinkle with 1/4 teaspoon salt and a few grinds of black pepper.
- In a medium saucepan, combine the heavy cream, chopped sage and rosemary, minced garlic, nutmeg, and a generous pinch of salt. Bring the cream mixture to a low boil over medium heat, then reduce heat to low and maintain a simmer. Simmer for about 10 minutes, or until the mixture has reduced by 1/4.
- Add the eggs to a medium bowl and whisk until lightly beaten. Slowly pour the hot cream mixture, while whisking continuously, into the eggs.
- Pour 1/3 of the cream and egg mixture over the first layer of potatoes in the prepared dish (about 2/3 cup). Sprinkle with 1/3 cup of Parmesan cheese, then add the next layer of potato slices and repeat twice (three total layers of potatoes).
- After adding the final layer of cream and cheese, cover the baking dish with foil. Bake covered for 40 minutes, or until the potatoes are tender.
- While the potatoes are baking, combine the Panko Bread Crumbs, remaining Parmesan cheese, Paprika, Garlic Powder, Onion Powder, pinch of Cayenne, and olive oil in a medium bowl.
- After the potatoes have been baked for 40 minutes, remove the foil. Carefully spread the breadcrumb mixture over the top of the potatoes and return to the oven. Bake uncovered for an additional 20 to 25 minutes, or until the bread crumbs are browned and the mixture is bubbling. Cool slightly before serving.
Comments & Reviews
Vanessa @ Cakes and Teacups says
This looks really nice and I love sweet potatoes : )
Noshing with the Nolands says
Thanks Vanessa.
Steve @ The Black Peppercorn says
Ooh wow – I SO love smoked chicken and these scalloped potatoes look so hearty and delicious! Thanks for sharing
Noshing with the Nolands says
Thanks for coming by Steve!!
Kari@Loaves and Dishes says
This is perfect for us indecisive people who can’t choose between regular potatoes and sweet potatoes!
Noshing with the Nolands says
Thanks Kari, I love sweet potatoes.