This Sweet Potato au Gratin recipe is the best of both worlds with savory cheeses and delicious sweet potato in one simple side dish that’s perfect for your next gathering or the holidays!
The Best Sweet Potato Au Gratin
We’re firm believers that cheese makes any dish better. And after making our fair share of au gratin recipes, we decided to try it out with one of our favorite side dish stars, the sweet potato. And we’re here to report that it works! Creamy cheeses plus bites of sweet potato is so delicious and we can’t wait for you to dig in!
Looking For More Au Gratin Recipes?
Then you have to try our delicata squash au gratin and our classic potatoes au gratin gruyere!
What You Will Need
- butter – Adds a rich buttery flavor to your homemade cheese sauce.
- garlic & yellow onion – Two simple but important ingredients that add the best savory favors.
- all-purpose flour – The base of the roux. Make this dish gluten-free by using gluten-free flour.
- dairy-free unsweetened, unflavored creamer – Helps to make the most creamy sauce! You can easily sub with half & half.
- chicken broth – Helps to get your sauce to the perfect consistency.
- kosher salt & ground black pepper – Just a bit to heighten all the other flavors.
- Gruyére cheese, Monterey Jack cheese, and parmesan cheese – Used in the sauce and sprinkled on top to get the cheesiest bites!
- sweet potatoes – One of our all time favorite side dish ingredients. If you love them too, check out our sweet potato casserole with marshmallows.
What’s The Difference Between Au Gratin Potatoes and Scalloped Potatoes?
Au gratin potatoes are usually sliced thinner than scalloped potatoes which are usually sliced 1/4 inch versus an 1/8th of an inch. Also, au gratin dishes are baked with layers of cheese between the potato slices while traditional scalloped potato dishes are baked with a cream sauce. Au gratin translates “to grate” in English, which makes sense, as it uses three different types of grated cheeses.
How To Make Sweet Potato Au Gratin
While your oven is preheating to 375 degrees F, gather and prep your ingredients. We love using our mandolin to get our sweet potatoes all the same thickness at about 1/8th of an inch.
Next, bring a large skillet to medium-high heat and add the butter and let it melt to coat the pan. Then add in the garlic and onions and move them around the pan until they’re softened, which will take around 2-3 minutes. Remove the onions and get started on your roux by letting 2 tablespoons of butter melt on your hot skillet and then whisk in the flour which will create a paste. While consistently whisking, slowly add in the creamer about a quarter cup at a time. Then add in the broth a quarter cup at a time. Let the sauce simmer to thicken and then add in the salt and pepper, and the cooked onions from earlier. If your sauce feels too thick, add a few splashes. of additional broth to thin it out.
Now it’s time to add the cheese! Remove your skillet from the heat and add in half of the gruyere cheese, half the monterey jack cheese, and all of the parmesan cheese. Give it all a good stir so that the cheese melts into your sauce.
Grated Cheese
For the meltiest cheese, avoid the pre-grated stuff and grate your own! Pre-grated cheese is coated with anti-caking agents, which prohibits the cheese from getting to its most melty state.
Grab your favorite 9×13 baking dish and spread about 1 cup of the cheese sauce on the bottom. Then add the sweet potatoes to the dish, stacking them in 3 rows down the pan.
How Do I Slice Potatoes For Au Gratin Potatoes?
The quickest way to get perfectly uniform potato slices is to use a mandolin slicer and set it to slice 1/8th inch slices. But please, please, please wear protective gloves when using a mandolin as it can quickly go from a super helpful kitchen tool to a lethal finger slicer. Trust us… we know from experience.
Cover the tops of the potato slices with the rest of the cheese sauce. Lastly, sprinkle the rest of the gruyere cheese and monterey jack cheese on the top.
Now cover your dish with tin foil and let it bake for 40 minutes. Then remove the tin foil and return it to the oven uncovered for 10 more minutes to allow the top to get nice and melty.
Pro Tip
To ensure all that melty cheese doesn’t stick to the foil when you remove it, tent your tin foil by putting a small crease down the center of it. This keeps all that cheese right where it’s supposed to be.
Now remove the whole dish from the oven and let it sit for 10-15 minutes before digging in!
Recipe FAQs and Tips
- Sweet Potatoes vs. Yams: We’re actually using yams in this recipe. These two root veggies often get mistaken for one another. Just look for a large, rich colored potato and you’ve grabbed the right kind.
- Gluten-Free: Make this recipe gluten-free by using gluten-free flour.
- Lighter Sauce: For a lighter sauce, we highly recommend using unsweetened and unflavored Nutpods.
- Storage: Store leftovers in an airtight container in the refrigerator for up to 3 days. Any longer and we’ve found that they get a bit too mushy for our liking.
Did you make these sweet au gratin potatoes and loved them?! We would love it if you would take a minute and leave a star rating and review – it is also helpful if you made any substitutions or changes to the recipe to share that as well. THANK YOU!
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Other Holiday Side Dishes You Might Like
Sweet Potato au Gratin
- Prep Time: 20 minutes
- Cook Time: 50 minutes
- Total Time: 1 hour 10 minutes
- Yield: 12 servings 1x
- Category: Side Dish
- Method: Stovetop + Oven
- Cuisine: American
Description
Our delicious Sweet Potato au Gratin recipe is a fun twist on traditional potatoes au gratin – perfect for the holidays or special occasion!
Ingredients
- 4 tablespoons butter, divided
- 1 teaspoon garlic, minced
- 1 small yellow onion, halved and thinly sliced
- 1/3 cup all-purpose flour or gluten-free flour
- 1 1/2 cups dairy-free unsweetened, unflavored creamer or half & half
- 1/2 cup chicken broth, more to thin
- 1 teaspoon kosher salt
- 1/4 teaspoon ground black pepper
- 1 1/2 cups Gruyére cheese, freshly shredded, divided
- 1 cup Monterey Jack cheese, freshly shredded, divided
- 1/2 cup parmesan cheese, grated
- 3–4 medium sweet potatoes (yams), sliced 1/8 inch thick*
Instructions
- Preheat: Preheat oven to 375 degrees F.
- Cook Onions: Bring a large cast iron skillet to a medium-high heat and add 2 tablespoons butter to melt. Swirl to coat pan. Add garlic and onions; move around pan until softened – about 2-3 minutes. Remove onions and set aside on a plate.
- Make Sauce: Keeping the hot skillet at a medium high heat, add the remaining 2 tablespoons of butter to melt. Whisk in the flour to create a roux or paste. Whisking consistently, gradually pour in the creamer about 1/4 cup at a time. Continue adding and whisking until all of the creamer is incorporated. Add broth the same way and continue whisking. Simmer gently to thicken a little bit and then add the salt, pepper, and onions back to the pan; stir to combine. If you feel you need to thin it out a little, simply add additional splashes of chicken broth until your desired consistency is reached.
- Add Cheese: Remove from heat and add half the gruyere cheese, half the monterey jack cheese, and all of the parmesan cheese. Stir to melt.
- Layer Potatoes: In a 9×13 baking dish, spread about 1 cup of the cheese sauce on the bottom of the pan. Add the sweet potatoes to the dish, stacking them in 3 rows down the pan. Cover the tops of the potato slices in the rest of the cheese sauce. Sprinkle the rest of the gruyere cheese and monterey jack cheese on top (feel free to add extra cheese on top, if desired).
- Bake: Cover with aluminum foil and bake in the preheated oven for 40 minutes. Remove the foil and return to the oven to bake, uncovered, for 10 more minutes.
- Rest & Serve: Remove from the oven and let rest for about 10-15 minutes and then serve!
Notes
- *Sweet Potatoes: we technically used yams in this recipe because typically people use the word “sweet potato” when they actually mean yams. Yams are larger and have a deeper orange color.
- Creamer: highly recommend using NutPods Original unsweetened/unflavored creamer for a slightly lighter sauce, but you can also use half & half.
- Gluten Free: simply use gluten-free flour instead of all-purpose flour.
Nutrition
- Serving Size: 4 o z
- Calories: 288
- Sugar: 6.6 g
- Sodium: 474.4 mg
- Fat: 13.9 g
- Carbohydrates: 29 g
- Protein: 12 g
- Cholesterol: 42.2 mg
Stefanie T says
Loved it!! Such a delicious swap for potatoes au gratin. The sweet potatoes were great with the homemade cheese sauce. I made this side dish for Thanksgiving on my Traeger. Smoked for approximately 60 min. If you love sweet potatoes, then this dish is for you!! My family loved it. Thank you Erin!
Erin says
So glad to hear that, Stephanie!!