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5 from 1 vote

Creamy, Cheesy, Sweet Potato Au Gratin Recipe

An easy, cheesy, sweet potato take on a November classic! This Sweet Potato Au Gratin replaces white potatoes with sweet potatoes, adds fresh herbs and aromatics, and three kinds of cheeses for a delicious, oven-baked potato casserole that will be gobbled up in no time! 
Prep Time10 minutes
Cook Time45 minutes
Total Time55 minutes
Course: Side Dish
Cuisine: American
Servings: 12


  • 3 sweet potatoes cut into 1/8 inch slices on mandolin slicer
  • 1 3/4 cups heavy cream
  • 4-5 cloves garlic minced
  • 2 tbsp unsalted butter melted
  • 1 1/2 cup gruyere cheese shredded
  • 1/2 cup Gouda shredded
  • 1/2 cup parmesan cheese shredded
  • 2 tbsp fresh thyme
  • salt and pepper to taste


  • Preheat your oven to 375°F
  • In a saucepan, melt the butter over medium heat. Add the minced garlic and cook for a minute or two until fragrant—add in the heavy cream and season with salt and pepper. Heat for a couple of minutes. (This mixture will not be super thick. But the sauce gets thicker as it cooks due to the potato starch).
  • Layer the sliced sweet potatoes in a greased baking dish. Season each layer with salt/pepper and thyme, sprinkle with the cheese 3 different types of cheese.
  • Pour the cream mixture over each layer of the sliced sweet potatoes, ensuring that the potatoes are well coated. I usually do 3-4 layers. Make sure not to add too much to each layer.
  • Sprinkle the remaining cheese mixture over the top of the dish.
  • Cover the baking dish with aluminum foil and bake for about 45 minutes.
  • Remove the foil and bake for an additional 15-20 minutes, or until the sweet potatoes are tender, and the top is golden brown and bubbling


Expert Tips

    • The cream mixture might seem thin when poured over the sweet potato slices initially. However, as the casserole cooks, the starch from the sweet potatoes works its magic, thickening the sauce. Don't worry if the cream isn't thick at first—it transforms into something amazing by the end of the cooking process.
    • Dairy-Free/Vegan: If you’re dairy-free or vegan, feel free to swap out the heavy cream, butter, and cheese for vegan alternatives. Silk makes a dairy-free heavy cream that would work well. Use vegan butter and a mixture of dairy-free cheese shreds and/or nutritional yeast. Let me know if you make it this way and how it turns out! 
    • Make-Ahead: If you have a busy day ahead, feel free to make this dish ahead of time– up to 48 hours in advance. Complete steps 2-5, then cover and refrigerate until you’re ready to serve it. Preheat your oven, let the casserole sit out for about 30 minutes to get to room temperature, then bake according to steps 7 and 8. 
    • Regular Potatoes: Feel free to swap out the sweet potatoes for Yukon gold potatoes or Russet potatoes. It won’t have the natural sweetness from the sweet potatoes, but it will be a savory, delicious side dish nonetheless. 

Serving Tips

Serve alongside your Thanksgiving dinner spread of stuffing, turkey, green beans, and more! Or make for an easy side dish for a weeknight or weekend family dinner! 

Storage Tips

Store leftovers in an airtight container for up to 3-4 days. Reheat individual portions or bake at 350F for 20 minutes or until warmed through. 


Calories: 306kcal | Carbohydrates: 13g | Protein: 11g | Fat: 24g | Saturated Fat: 15g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 6g | Trans Fat: 0.1g | Cholesterol: 76mg | Sodium: 306mg | Potassium: 264mg | Fiber: 2g | Sugar: 4g | Vitamin A: 8884IU | Vitamin C: 4mg | Calcium: 332mg | Iron: 1mg