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If you are looking for the ultimate fall side dish, make Sweet Potato Au Gratin. It is loaded with savory flavor that is easy to make with simple ingredients.

Baked Sweet Potato Au Grating in a white baking dish
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Sweet potato recipes always make the best side dish recipes. We always make Crockpot Sweet Potato Casserole Recipe for the holidays. But these sweet potato au gratin takes our classic Potatoes Au Gratin Recipe to the next level.

You will love the creamy sauce, amazing flavor and how tender the sweet potatoes cook.

Why We Love This Recipe

Sweet Potato Au Gratin is made with two different types of cheeses that can easily be changed. We have even added in parmesan cheese with fresh herbs.

The prep time is easy and these sweet potatoes make the best side dish that everyone will love.

Ingredients

Ingredients - Sweet Potatoes, Heavy Cream, Garlic, Salt, Pepper, Nutmeg, Grueyre Cheese, Sharp Cheese
  • Sweet Potatoes – Peeled and Sliced 1 / 8-inch thick. You can even use russet potatoes
  • Cloves Garlic – Learn How to Mince Garlic Cloves
  • Butter – Cut into small pieces. We used unsalted butter

Scroll to the bottom for the full recipe in the recipe card.

How to Make Sweet Potato Au Gratin

  • Step 1 – Preheat the oven to 375°F. Grease a 9×13 inch baking dish.
Combining heavy cream with seasoning in a large pot with a wooden spoon

Step 2 – In a large saucepan, combine the heavy cream, minced garlic, salt, black pepper, and nutmeg. Heat over medium heat until it just starts to simmer. Remove from heat and set aside.

Sliced Sweet Potatoes in a baking dish

Step 3 – Layer half of the sliced sweet potatoes in the prepared baking dish, slightly overlapping the slices.

Pouring the sauce over the slice sweet potatoes in the baking dish

Step 4 – Drizzle half of the cream mixture over the remaining potatoes.

Topping the slice sweet potatoes with shredded cheese in a baking dish

Step 5 – Sprinkle half of the Gruyère Cheese and half of the cheddar cheese over the cream. We have even added in fresh thyme for added flavor.

Slice sweet potatoes in a baking dish topped with shredded cheese and pieces of butter

Step 6 – Repeat with another layer of sweet potatoes, the remaining cream mixture, and the remaining cheeses. Top with the pieces of butter.

Baking dish topped with aluminum foil

Step 7 – Cover the dish tightly with aluminum foil. Bake for 30 minutes.

  • Step 8 – Remove the foil and continue baking for an additional 25-30 minutes, or until the sweet potatoes are tender when pierced with a fork and the top is golden brown and bubbly.
  • Step 9 – Let the dish rest for 10 minutes before serving.

Expert Tips

  • Heavy Cream Mixture – When heating the heavy cream, only bring it to a light simmer. Avoid boiling the mixture, as it may reduce too much or cause the cream to separate. If your cream thickens too much while simmering, remove it from heat earlier. 
  • Sweet Potato Slices – When layering the sweet potatoes, try to slightly overlap each slice. This helps the dish stay compact and ensures that each bite has layers of the sweet potato and cheese. 
  • Casserole Dish – Prepare the casserole dish by spraying with cooking spray. This helps with cleanup and to easily serve the sweet potatoes. We have used a cast iron skillet to make this recipe.
Sweet Potatoes Au Gratin on a serving spoon

Serving Suggestions

Sweet Potato Au Gratin makes a delicious side dish served for Christmas, Thanksgiving or your next weeknight meal.

Serve these au gratin potatoes with these family favorite recipes.

Frequently Asked Questions

How to Slice Sweet Potatoes for this Recipe?

Try to slice the sweet potatoes as evenly as you can (about ⅛ inch thick) so they cook evenly. A Mandolin slicer makes it super quick and easy, but if you’re slicing by hand, just take your time to keep the thickness the same. You can use a sharp knife on a cutting board.

How to Store Leftovers

Store the leftovers in an airtight container in the refrigerator for up to 5 days.

How to Reheat Sweet Potato Gratin

Reheat the leftovers in the microwave or in the oven in the baking dish.

Serving of sweet potato au grating on a plate

More Easy Sweet Potatoes Recipes

If you make these Sweet Potato Au Gratin Recipe, please leave us a comment or a star review. We love to hear from you.

Sweet Potato Au Gratin

5 from 2 votes
If you are looking for the ultimate fall side dish, make Sweet Potato Au Gratin. It is loaded with savory flavor that is easy to make with simple ingredients.
Prep Time 25 minutes
Cook Time 1 hour
Let the dish rest 10 minutes
Total Time 1 hour 35 minutes
Servings 8
Cuisine American
Course Side Dish
Calories 520

Ingredients

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Instructions

  • Preheat the oven to 375°F. Grease a 9×13 inch baking dish.
  • In a large saucepan, combine the heavy cream, minced garlic, salt, black pepper, and nutmeg. Heat over medium heat until it just starts to simmer. Remove from heat and set aside.
  • Layer half of the sliced sweet potatoes in the prepared baking dish, slightly overlapping the slices.
  • Pour half of the cream mixture over the sweet potatoes.
  • Sprinkle half of the Gruyere cheese and half of the cheddar cheese over the cream.
  • Repeat with another layer of sweet potatoes, the remaining cream mixture, and the remaining cheeses. Top with the pieces of butter.
  • Cover the dish tightly with aluminum foil. Bake for 30 minutes.
  • Remove the foil and continue baking for an additional 25-30 minutes, or until the sweet potatoes are tender when pierced with a fork and the top is golden brown and bubbly.
  • Let the dish rest for 10 minutes before serving.

Recipe Notes

Try to slice the sweet potatoes as evenly as you can (about ⅛ inch thick) so they cook evenly. A mandoline slicer makes it super quick and easy, but if you’re slicing by hand, just take your time to keep the thickness the same. 
When heating the heavy cream, only bring it to a light simmer. Avoid boiling the mixture, as it may reduce too much or cause the cream to separate. If your cream thickens too much while simmering, remove it from heat earlier. 
When layering the sweet potatoes, try to slightly overlap each slice. This helps the dish stay compact and ensures that each bite has layers of the sweet potato and cheese. 

Nutrition Facts

Calories 520kcal, Carbohydrates 37g, Protein 13g, Fat 36g, Saturated Fat 22g, Polyunsaturated Fat 1g, Monounsaturated Fat 9g, Trans Fat 0.1g, Cholesterol 110mg, Sodium 632mg, Potassium 663mg, Fiber 5g, Sugar 9g, Vitamin A 25448IU, Vitamin C 5mg, Calcium 343mg, Iron 1mg

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About the Author

Hi, I’m Carrie. Welcome to Eating on a Dime!

I’m on a mission to help you cook delicious meals without busting your budget. Together we are going to cook real food… for real families!

5 from 2 votes

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Comments

  1. Carrie Barnard says:

    Thank you Becky!

  2. Becky says:

    5 stars
    Yum

  3. Casey says:

    5 stars
    Loved the flavor of the sweet potatoes!