Quick Look: Scalloped Sweet Potatoes au Gratin
- Ready In: 1 hour 10 minutes
- Serves: 12
- Main Ingredients: orange sweet potatoes (a.k.a. yams), onion, Gruyère cheese, Monterey Jack cheese, Parmesan, flour, broth, and a dairy-free creamer (or half & half).
- Dietary Info: gluten-free friendly and use vegetable broth to make it vegetarian
- Best For: Thanksgiving, Christmas, or a special occasion
- Flavor-Profile: a savory twist on the traditional potatoes au gratin with the richness of a three cheese sauce and a subtle sweetness from the potatoes.
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Key Ingredients + Substitutions
Be sure to see the recipe card below for a full listing of ingredients, instructions, and estimated nutritional information.
- Sweet Potatoes – orange-fleshed sweet potatoes commonly sold as yams in U.S. grocery stores.
- Creamer – highly recommend using a dairy-free unflavored creamer in the sauce to lighten it a bit. The blend of three cheeses provides enough richness.
- Flour – simply swap the all-purpose flour for gluten-free flour to make this recipe gluten-free.
- Cheese – freshly shred each cheese for maximum meltiness.
How To Make Sweet Potato Au Gratin
Step 1 – Cut the sweet potatoes into 1/8″ thick slices.
Step 2 – Sauté the onions and garlic in butter. Remove, melt more butter and whisk in the flour to make a roux.
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 1/8-inch slices. 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.
Step 3 – Gradually whisk in the creamer, broth, and seasonings.
Step 4 – Add half the Gruyère and Monterey Jack cheeses, all of the Parmesan, and the cooked onions. Mix to melt and combine.
Step 5 – Spread about 1 cup of cheese sauce in the bottom of a 9×13 pan.
Step 6 – Stack the sliced potatoes in three rows down the pan, allowing them to loosely lean against each other.
Step 7 – Pour the rest of the cheese sauce on top of the potatoes.
Step 8 – Add the remaining shredded cheese on top, cover with foil, and bake.
Erin’s Testing Tips: What We Learned
– Three-Cheese Sauce: we used a combination of Gruyère, Monterey Jack, and Parmesan cheese to give this homemade cheese sauce a greater depth of flavor and richness.
– Baking Time: we adjusted the baking time during testing to make sure the sweet potatoes were fully cooked through. They should be fork-tender and the sauce should be bubbling when done.
– Foil Tip: to keep the cheese from sticking to the aluminum foil cover, make a crease down the center of it to tent the foil over the pan. You could also spray it with non-stick cooking spray, because nobody wants to remove delicious melty cheese with the cover.
Best Ways To Serve Sweet Potatoes au Gratin
This crowd-pleasing side dish can be enjoyed right alongside an herb butter turkey, orange glazed ham, or perfectly grilled prime rib at your holiday table. Feel free to add other traditional side dishes for the most delicious dinner!
Other Holiday Side Dishes You Might Like
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Ingredients
- 4 tablespoons butter, divided (sub plant-based butter)
- 1 yellow onion, halved and thinly sliced
- 1 teaspoon garlic, minced
- ⅓ cup all-purpose flour, sub gluten-free flour
- 1 ½ cups dairy-free unsweetened unflavored creamer, sub half & half
- ½ cup chicken broth, more to thin, if needed
- 1 teaspoon kosher salt
- ¼ teaspoon ground black pepper
- 1 ½ cups Gruyère cheese, freshly shredded, divided
- 1 cup Monterey Jack cheese, freshly shredded, divided
- ½ cup parmesan cheese, shredded
- 3-4 medium sweet potatoes (or yams), sliced ⅛ inch thick*
Instructions
- Preheat: Preheat oven to 375℉.
- 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 sliced onions and 1 teaspoon garlic; move around pan until softened – about 2-3 minutes. Remove them and set aside on a plate.
- Make Sauce: Keeping the skillet at a medium-high heat, add the remaining 2 tablespoons butter to melt. Whisk in ⅓ cup all-purpose flour to create a roux or paste. Whisking consistently, gradually pour in 1 ½ cups dairy-free unsweetened unflavored creamer; about ¼ cup at a time. Continue adding and whisking until all of the creamer is incorporated. Add ½ cup chicken broth the same way and continue whisking. Simmer gently to thicken a bit and then add 1 teaspoon kosher salt, ¼ teaspoon ground black pepper, and the 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 gruyère cheese, half the monterey jack cheese, and ½ cup 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 sliced sweet potatoes to the dish, stacking them in 3 rows down the pan. Pour the rest of the cheese sauce over the tops of the potato slices. Sprinkle the rest of the gruyère cheese and monterey jack cheese on top (feel free to add extra cheese, 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. It is done when the sweet potatoes are fork-tender and the sauce is bubbling with melted cheese.
- Rest & Serve: Remove from the oven and let rest for about 10-15 minutes and then serve!
Notes
- *Sweet Potatoes: We used orange-fleshed sweet potatoes, which are commonly labeled as “yams” in U.S. grocery stores.
- Creamer: highly recommend using NutPods Original unsweetened/unflavored creamer for a slightly lighter sauce, but you can also use half & half.
- Gluten Free: use gluten-free flour instead of all-purpose flour.
- Storage: leftovers can be kept in an airtight container in the fridge for 3-4 days.
Bridget says
Love this spin on the classic! Very yummy!
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!!