Every year for Thanksgiving, I make this sweet potato au gratin recipe! It's such a delicious combination of cheese, sweet potato slices, onions, fresh herbs, and garlic. Here's exactly how I make it!
Every year for Thanksgiving, I make this sweet potato au gratin recipe! It's such a delicious combination of cheese, sweet potato slices, onions, fresh herbs, and garlic. Here's exactly how I make it!
You’ll love this sweet potato au gratin recipe
It's delicious. I love swapping traditional russet potatoes for sweet potatoes in this au gratin recipe! The sweet potatoes paired with two different kinds of cheeses, fresh garlic, butter and fresh herbs make for the ultimate comfort food dish!
It's customizable. I personally love the combination of gruyere cheese and cheddar cheese, but one of the best things about this delicious sweet potato gratin is that it's customizable! You can use any of your favorite cheeses.
It's sure to be a crowd favorite. If you make these for your next holiday dinner, you will absolutely be the crowd favorite! This dish is so much more flavorful than traditional gratins.
Ingredients
Sweet Potatoes. Sweet potatoes are always a must, especially for a Thanksgiving dinner table! However, instead of the traditional mashed sweet potato casserole, I love using them to make this sweet potato au gratin. It's seriously the perfect side dish.
Yellow Onion. To add another flavor level, I like to add thinly sliced yellow onions in between the scalloped sweet potato slices.
Garlic. Fresh garlic is an absolute must because I actually brown the garlic in the butter along with fresh herbs to really add a punch of flavor to the cream sauce.
Butter. Butter is an absolute must! The base of the cheese sauce is a roux, and part of that includes butter. I really recommend sticking with the butter and not using olive oil as a substitute.
Fresh Thyme + Rosemary. Fresh thyme and rosemary are an absolute must! It really turns this into a savory sweet potato gratin recipe. Plus, thyme and rosemary just taste like the holidays!
Flour. Just like the butter, the flour is a necessary ingredient to create a roux.
Heavy Cream. I prefer to use heavy cream to make the best creamy sauce, but you can also use any cow's milk you prefer.
Shredded Cheese. I like using a combination of gruyere and sharp cheddar, but there are so many other great options for this cheesy sweet potato gratin recipe!
How to make this sweet potato au gratin
- Preheat your oven to 350F.
- Thinly slice your sweet potatoes and onion.
- Place your sweet potatoes in rows, similar to scalloped potatoes in a casserole dish.
- Place your onions in between every 2-3 potatoes and set aside.
- In a large frying pan, melt your 3 tablespoon of butter.
- Once melted, add in your 2 cloves of minced garlic, 1 tablespoon fresh thyme and 1 tablespoon fresh rosemary.
- Over low heat, let the garlic cook in the butter until a light golden brown. This should be 7-10 minutes.
- Once the garlic is a light golden brown, whisk in your 3 tablespoon of butter. Continue to whisk until you have a golden brown paste looking mixture.
- Whisk in your heavy cream in ½ cup increments. You'll want to be sure there are no clumps before adding more milk.
- Once all your milk is mixed in, continue to stir and bring the mixture to a boil over medium heat.
- Remove from the heat and add in 1 c. cheddar + 1 c. gruyere.
- Once the cheese is fully melted into the mix, pour over your sweet potatoes + onions.
- Spread the mixture to make sure it evenly covers the 9x13 pan.
- Cover with aluminum foil and allow to bake for 30 minutes.
- After 30 minutes, remove the aluminum foil and bake uncovered for 20 minutes.
- Lastly, after 50 minutes, turn your broil on low and let the potatoes broil for 7-10 minutes, or until the top is nice and bubbly and golden brown.
- Allow your potatoes to cool for 15 - 20 minutes after broiling.
- Serve and enjoy!
Tips for making the best sweet potato au gratin
Slicing the potatoes. If you want to easily slice the potatoes, you can always use a mandolin slicer! If you don't have a mandolin slicer, I recommend making sure you have a sharp knife.
Grated cheese. If you can, I absolutely recommend shredding your cheese yourself! It makes all the difference in the cream mixture.
Substitutions and variations
Sweet Potatoes. If you don't have sweet potatoes or don't like sweet potatoes, you can always use russet potatoes or Yukon gold potatoes.
Fresh Herbs. If you don't have fresh rosemary and thyme, you can use dried.
Cheese. Other cheeses that would be great for this sweet potatoes au gratin would be Swiss, Monterey jack, gouda, or parmesan cheese!
Storing and reheating sweet potato gratin
If you are bringing these cheesy sweet potatoes to a holiday dinner, cover with aluminum foil or plastic wrap. Remove the cover and bake at 350F for 15-20 minutes until heated through.
If you are looking to store leftovers, store them in an airtight container in the fridge. I like reheating them by placing them in a skillet over medium-low heat. Add a drop of water, cover, and let it heat through for about 5-10 minutes.
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Want more Thanksgiving side dishes?
Sweet Potato Au Gratin
Every year for Thanksgiving, I make this sweet potato au gratin recipe! It's such a delicious combination of cheese, sweet potato slices, onions, fresh herbs, and garlic. Here's exactly how I make it!
Ingredients
- 3-4 large sweet potatoes, sliced
- ½ sweet onion, thinly sliced
- 3 tablespoon butter
- 2-3 cloves garlic
- 1 tablespoon fresh thyme
- 1 tablespoon fresh rosemary
- 3 tablespoon flour
- 2 cups milk
- 2 cups cheese (I used 1 cup gruyere and 1 cup cheddar)
Instructions
- Preheat your oven to 350F.
- Thinly slice your sweet potatoes and onion.
- Place your sweet potatoes in rows, similar to scalloped potatoes in a casserole dish.
- Place your onions in between every 2-3 potatoes and set aside.
- In a large frying pan, melt your 3 tablespoon of butter.
- Once melted, add in your 2 cloves of minced garlic, 1 tablespoon fresh thyme and 1 tablespoon fresh rosemary.
- Over low heat, let the garlic cook in the butter until a light golden brown. This should be 7-10 minutes.
- Once the garlic is a light golden brown, whisk in your 3 tablespoon of butter. Continue to whisk until you have a golden brown paste looking mixture.
- Whisk in your heavy cream in ½ cup increments. You'll want to be sure there are no clumps before adding more milk.
- Once all your milk is mixed in, continue to stir and bring the mixture to a boil over medium heat.
- Remove from the heat and add in 1 c. cheddar + 1 c. gruyere.
- Once the cheese is fully melted into the mix, pour over your sweet potatoes + onions.
- Spread the mixture to make sure it evenly covers the 9x13 pan.
- Cover with aluminum foil and allow to bake for 30 minutes.
- After 30 minutes, remove the aluminum foil and bake uncovered for 20 minutes.
- Lastly, after 50 minutes, turn your broil on low and let the potatoes broil for 7-10 minutes, or until the top is nice and bubbly and golden brown.
- Allow your potatoes to cool for 15 - 20 minutes after broiling.
- Serve and enjoy!
Notes
Tips for making the best sweet potato au gratin
Slicing the potatoes. If you want to easily slice the potatoes, you can always use a mandolin slicer! If you don't have a mandolin slicer, I recommend making sure you have a sharp knife.
Grated cheese. If you can, I absolutely recommend shredding your cheese yourself! It makes all the difference in the cream mixture.
Substitutions and variations
Sweet Potatoes. If you don't have sweet potatoes or don't like sweet potatoes, you can always use russet potatoes or Yukon gold potatoes.
Fresh Herbs. If you don't have fresh rosemary and thyme, you can use dried.
Cheese. Other cheeses that would be great for this sweet potatoes au gratin would be Swiss, Monterey jack, gouda, or parmesan cheese!
Storing and reheating sweet potato gratin
If you are bringing these cheesy sweet potatoes to a holiday dinner, cover with aluminum foil or plastic wrap. Remove the cover and bake at 350F for 15-20 minutes until heated through.
If you are looking to store leftovers, store them in an airtight container in the fridge. I like reheating them by placing them in a skillet over medium-low heat. Add a drop of water, cover, and let it heat through for about 5-10 minutes.
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