If you’ve ever embarked on the delicious journey of making au gratin potatoes, only to be met with a watery disappointment or stubbornly undercooked slices, you’re not alone. I understand the frustration of recipes that don’t quite hit the mark. That’s why I’ve meticulously tested and perfected this Sweet Potato Au Gratin recipe, ensuring it consistently delivers a show-stopping side dish without the guesswork. This recipe features tender, sweet potato layers bathed in a rich, creamy, and exquisitely cheesy sauce that is anything but bland. My secret? A knack for seasoning that transforms simple ingredients into a symphony of flavors.
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This isn’t just a dish; it’s a culinary embrace, a true comfort food masterpiece! Forget the notion of a “healthy” recipe here; this is about indulgence and pure enjoyment. It’s the kind of dish you reserve for special occasions—think festive Sunday dinners, holiday feasts (it makes an absolutely amazing Thanksgiving side!), or simply any day you crave a luxurious treat. Go ahead, pamper your palate!
Perhaps you’ve savored my other cheesy, comforting creations like Scalloped Corn, Instant Pot Scalloped Potatoes, or Zucchini Au Gratin. This sweet potato version offers that same beloved flavor profile, presented with its own unique and irresistible charm.
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A Creamy and Cheesy Delight: Sweet Potato Au Gratin
Sweet Potato Au Gratin is a beloved classic that elevates the humble sweet potato to new heights of deliciousness. This dish, often associated with holiday feasts and festive gatherings, combines thinly sliced sweet potatoes with a rich, velvety cheese sauce, all baked to golden perfection. Unlike many sweet potato dishes that lean towards sugary, dessert-like profiles, this au gratin recipe embraces a savory approach, highlighting the natural sweetness of the potatoes with robust, salty cheese and aromatic spices. It’s a harmonious blend that creates a truly irresistible side dish, perfect for complementing any main course or standing proudly on its own.
Sweet Potatoes Au Gratin Ingredients
Crafting the perfect Sweet Potato Au Gratin requires a selection of fresh, high-quality ingredients that harmonize to create its signature rich and creamy texture and savory flavor. Here’s what you’ll need to gather:
- Sweet Potatoes: The star of our dish. Choose firm, blemish-free sweet potatoes for the best results.
- Butter: Essential for sautéing and forming the base of our luxurious cheese sauce.
- Garlic: Freshly minced garlic adds an aromatic depth that perfectly complements the sweet potatoes and cheese.
- Cream Cheese: A secret ingredient that contributes to the sauce’s incredible creaminess and a subtle tang.
- Heavy Cream: The foundation for a truly decadent and smooth sauce. Its richness is key to the au gratin texture.
- Cheddar Cheese: Sharp or medium cheddar provides a classic, tangy cheese flavor that pairs wonderfully with sweet potatoes.
- Parmesan Cheese: Adds a salty, umami kick and contributes to the golden crust.
- Mozzarella Cheese: Known for its superior melt and stretch, mozzarella ensures a gooey, cheesy top layer.
- Onion Powder, Salt, and Pepper: These seasonings are crucial for balancing and enhancing all the flavors, bringing everything together beautifully.
Using a variety of cheeses ensures a complex flavor profile and a superior melting experience, creating layers of cheesy goodness throughout the dish. Freshly grating your cheeses is highly recommended for optimal melt and flavor, as pre-shredded varieties often contain anti-caking agents that can affect texture.
How to Slice the Sweet Potatoes
Achieving perfectly tender and evenly cooked sweet potato au gratin starts with uniform slicing. My preferred method is to slice the sweet potatoes into precise ¼-inch rounds. This thickness ensures they cook through evenly without becoming mushy or staying undercooked. For consistent results, I highly recommend using a mandoline slicer, like this excellent option available on Amazon. A mandoline makes quick work of slicing and guarantees uniform thickness, which is crucial for this dish.
If you don’t have a mandoline, you can still achieve great results with a sharp knife and a steady hand. Aim for slices as close to ¼-inch thick as possible. While ½-inch thick slices will also work, keep in mind they may require a slightly longer baking time to reach optimal tenderness. The key is consistency – try to make all your slices the same thickness so they cook uniformly, preventing some from being firm while others are overdone. Be mindful and careful when slicing, especially if using a mandoline, to ensure safety.
How to Make Sweet Potato Au Gratin: Step-by-Step
This recipe is surprisingly straightforward, delivering impressive results with simple steps. For detailed measurements and full instructions, please refer to the comprehensive recipe card at the bottom of this post. Here’s an overview of the process:
- **Prepare the Oven:** Begin by preheating your oven to 350 degrees Fahrenheit (175 degrees Celsius). This ensures the oven is at the correct temperature when the dish is ready to bake, promoting even cooking.
- **Start the Sauce Base:** In a medium saucepan, melt the butter over medium heat. Butter adds a rich, foundational flavor to our cheese sauce.
- **Infuse with Garlic:** Once the butter is melted and shimmering, add the minced garlic. Cook it for about two minutes, stirring constantly, until it becomes wonderfully fragrant. Be careful not to let it brown, as burnt garlic can taste bitter.
- **Build the Cheesy Sauce:** Reduce the heat to low. Stir in the cream cheese, heavy whipping cream, grated Parmesan Reggiano, and half a cup of the shredded cheddar cheese. Continue stirring gently until all the cheeses begin to melt and combine.
- **Season to Perfection:** Add the onion powder, along with salt and freshly ground black pepper to taste. It’s crucial to taste the sauce at this stage and adjust the seasonings as needed. The sweet potatoes will absorb some of the flavor, so make sure the sauce is well-seasoned.
- **Achieve Creaminess:** Continue to stir the sauce continuously over low heat until all the cheese has completely melted and the sauce is smooth and creamy, without any lumps. Remove it from the heat and set aside to cool slightly.
- **Layer the Potatoes:** Arrange your uniformly sliced sweet potatoes in neat, overlapping rows within a 9×13-inch baking dish. Try to create even layers for consistent cooking.
- **Drizzle with Sauce:** Evenly drizzle the rich, creamy cheese sauce over the arranged sweet potato slices, ensuring every layer is coated generously.
- **Top with More Cheese:** Sprinkle the remaining ½ cup of shredded cheddar cheese and all the mozzarella cheese over the top layer of potatoes and sauce. This will form a beautiful, bubbly, golden crust.
- **Bake to Perfection:** Cover the baking dish tightly with aluminum foil. Bake in the preheated oven for 30 minutes. This initial covered baking period allows the potatoes to steam and soften without drying out.
- **Uncover and Finish:** Remove the foil and continue baking for an additional 25 minutes, or until the sweet potatoes are fork-tender and the cheese on top is golden and bubbling.
- **Crispy Top Option (Broil):** For an extra crispy, golden-brown topping, turn on the broiler during the last 1-3 minutes of baking (uncovered), keeping a close eye on it to prevent burning.
- **Rest Before Serving:** Allow the au gratin to cool and set for at least 30 minutes before slicing and serving. This resting period is crucial for the sauce to thicken slightly and for the layers to hold together beautifully.
Sweet Potato Au Gratin Recipe Card
Brandi Crawford
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Equipment
- 9×13 Baking Dish
- Mandoline Slicer
Ingredients
- 2 pounds sweet potatoes Sliced into ¼ or ½ inch rounds.
- 1 tablespoon butter
- 2 garlic cloves minced
- 4 oz cream cheese
- ¼ cup heavy whipping cream
- 1 cup shredded cheddar cheese Divided into ½ cup portions.
- ¼ cup shredded parmesan reggiano cheese
- 1 teaspoon onion powder
- salt and pepper to taste
- ½ cup shredded mozzarella cheese
Instructions
- Preheat oven to 350 degrees F (175 C).
- Heat a saucepan on medium heat and add the butter.
- When melted, add the garlic and cook for a couple of minutes until fragrant, being careful not to brown.
- Reduce heat to low. Add in the cream cheese, whipping cream, Parmesan Reggiano, and ½ cup shredded cheddar cheese. Stir. Add in the onion powder, salt, and pepper to taste. Taste the sauce repeatedly and adjust the flavor as needed for optimal seasoning.
- Stir continuously until all the cheese has melted into a smooth, creamy sauce.
- Remove from the heat and set aside.
- Arrange the sliced sweet potatoes in even, overlapping rows throughout a 9×13 baking dish. Drizzle the cheese sauce generously over the potatoes.
- Sprinkle the remaining ½ cup of shredded cheddar and the mozzarella evenly throughout the pan.
- Cover with foil and bake for 30 minutes.
- Remove the foil and bake an additional 25 minutes until the sweet potatoes are tender and the top is golden and bubbly.
- For a crispier top, turn on the Broil function for 1-3 minutes before the dish has finished baking, watching closely to prevent burning.
- Cool for 30 minutes before serving to allow the sauce to set and the flavors to meld.
Notes
- You can reduce the amount of fat in the recipe by using low-fat cream cheese and cheese in the recipe. You can also lessen the overall amount of cheese used if desired.
Nutrition
Nutrition Data Disclaimer
Macros are provided as a courtesy and should not be construed as a guarantee. This information is calculated using MyFitnessPal.com. To obtain the most accurate nutritional information in a given recipe, you should calculate the nutritional information with the actual ingredients used in your recipe, using your preferred nutrition calculator. You are solely responsible for ensuring that any nutritional information provided is accurate, complete, and useful.
Frequently Asked Questions and Pro Tips
Here are some common questions and expert tips to help you master your Sweet Potato Au Gratin:
While often used interchangeably when referring to potato dishes, there’s a subtle distinction. Both are casserole-like and feature creamy sauces. Traditionally, scalloped potatoes are made with heavy cream and milk, creating a simpler, thinner sauce without grated cheese between the layers. Au gratin, on the other hand, always incorporates grated cheese, not just in the sauce but often layered throughout and as a crunchy topping. Many au gratin recipes also call for breadcrumbs for an extra crispy crust. In this sweet potato au gratin, we achieve a similar crispiness by broiling the dish briefly at the end, toasting the cheese to a golden perfection. You can delve deeper into The Difference Between Scalloped and Au Gratin for more insights.
In most American grocery stores, what’s labeled as a “yam” is typically just a type of sweet potato. True yams are a distinct vegetable, much starchier and drier, with a bumpy, tough, brown skin, and are primarily used in Caribbean and West African cuisines. You’ve likely never encountered a true yam unless you’ve sought them out in specialty markets. Many years ago, particularly in the Southern United States (Louisiana especially), the term “yam” became a common nickname for the softer, orange-fleshed sweet potatoes. So, the “candied yams” you might see are almost always candied sweet potatoes. For a detailed explanation, check out The Difference Between Yams and Sweet Potatoes.
For this recipe, I find that a combination of sharp cheddar, Parmesan Reggiano, and mozzarella delivers the best balance of flavor and texture. Cheddar provides a tangy depth, Parmesan adds a salty, nutty bite, and mozzarella ensures that wonderfully gooey, stretchy melted cheese effect. However, feel free to experiment with your favorite cheeses! Gruyere, Fontina, or even a smoked Gouda would also be delicious additions. A crucial tip: always purchase block cheese and grate it yourself. Pre-shredded cheeses often contain anti-caking agents like cellulose or corn starch, which can prevent them from melting as smoothly and result in a less creamy sauce. Freshly grated cheese melts beautifully, creating that luxurious, seamless sauce we aim for.
Unlike many sweet potato dishes that are loaded with cinnamon, brown sugar, or marshmallows, this au gratin offers a distinctly savory take. While sweet potatoes inherently possess a natural sweetness, the robust, salty, and tangy flavors from the blend of cheeses, garlic, and onion powder transform it into a rich, savory side. It’s designed to be a cheesy, flavorful complement to your main meal, not a dessert-like accompaniment. The contrast between the sweet potato and the savory cheese sauce is what makes this dish so incredibly satisfying.
Absolutely! This Sweet Potato Au Gratin can be assembled a day in advance, making it perfect for holiday meal prep. To prepare ahead, assemble the dish as instructed, stopping before baking. Tightly cover the baking dish with plastic wrap, pressing the wrap directly onto the surface of the potatoes to minimize air exposure, which helps prevent discoloration (browning). Store it in the refrigerator. When you’re ready to bake, remove it from the fridge and allow it to come closer to room temperature for about 30 minutes before baking as directed. While the top potatoes might show slight browning overnight, the cheese and baking process should beautifully conceal it.
Once baked, store any leftovers tightly sealed and covered in an airtight container in the refrigerator. It will remain delicious for 3-4 days. For reheating, the oven is your best friend to maintain its creamy texture and prevent it from becoming watery. Reheat at 350 degrees F (175 C) until thoroughly warmed through.
Many people hesitate to freeze dishes with heavy cream and butter due to concerns about separation. While it’s true that dairy can sometimes separate upon thawing, I often freeze this dish with great success. You might notice some slight textural changes, but it doesn’t detract significantly from the overall enjoyment for me. To reheat from frozen, place the covered dish directly into a preheated oven at 350 degrees F (175 C) and bake until heated through, approximately 45-60 minutes, or until bubbling. If needed, remove the foil for the last 10-15 minutes to re-crisp the top. Freezing individual portions in oven-safe containers can also be a convenient option for quick weeknight meals.
More Sweet Potato Recipes to Savor
If you love sweet potatoes as much as I do, be sure to explore these other fantastic recipes:
Southern Candied Sweet Potatoes
Southern Sweet Potato Casserole
Sweet Potato Beef Chili
Air Fryer Sweet Potato FriesHealthy Sweet Potato Pie
Healthy Sweet Potato Fries
Sweet Potato Cornbread
Mashed Sweet Potatoes with Brown Sugar
This Sweet Potato Au Gratin pairs beautifully with classic comfort dishes. Try serving it alongside Homemade Creamed Corn and a delicious Southern Baked Ham With Pineapple for an unforgettable meal.
Check out our list of The Best Authentic Soul Food Recipes here for more culinary inspiration.