Cheesy Sweet Potato Au Gratin
Have you ever wanted a side dish that steals the show? Well, you’ve found it! This creamy, cheesy Sweet Potato Au Gratin is the real deal. It’s a creamy, cheesy, and delicious twist on the classic.
I used to think potatoes au gratin could only be one way, but boy, was I wrong. This dish is perfect for holidays, family dinners, or anytime you just want something comforting. It’s simple, savory, and has just a hint of sweetness.
Why You’ll Love Sweet Potato Au Gratin
You are going to fall head over heels for this recipe! The sweet potatoes become so tender, and they soak up all the cheesy, garlicky cream sauce. It’s the perfect mix of sweet and savory in every single bite.
This dish feels fancy, but it’s a piece of cake to make. It’s a wonderful change from a classic Pecan Sweet Potato Casserole and has all the comforting vibes of a Loaded Baked Potato Casserole.
Your friends and family will ask for this recipe again and again. It’s just that good! It will be the star of your dinner table.
Ingredients You’ll Need
Here are the simple things you need to make this cheesy magic. You can find the exact amounts on the recipe card below!
- Sweet Potatoes: These are the star of the show, bringing natural sweetness.
- Heavy Cream: This makes the sauce rich, dreamy, and oh-so-creamy.
- Gruyere Cheese: I love its nutty flavor that melts into pure goodness.
- Parmesan Cheese: This adds a wonderful salty and sharp bite to the dish.
- Garlic: You can’t go wrong with garlic for a boost of flavor.
- Thyme: Fresh thyme adds a lovely, earthy touch that tastes amazing.
- Butter: This helps make everything rich and keeps the dish from sticking.
- Salt and Pepper: You’ll need these to bring all the flavors to life.
How to Make Sweet Potato Au Gratin
Making this dish is so easy! Just follow these simple steps, and you will have a beautiful gratin ready for the oven.
Step 1: Get Your Oven and Potatoes Ready
First, preheat your oven to 400°F (200°C). Grease a 9×13-inch baking dish with 1 tablespoon of butter. Then, carefully slice 3 pounds of sweet potatoes into 1/8-inch thick rounds using a mandoline slicer.
Step 2: Make the Creamy Sauce
In a large saucepan, melt 3 tablespoons butter over medium heat. Add 2 minced garlic cloves and cook for one minute until you can smell them. Pour in 1 ½ cups heavy cream and bring it to a gentle simmer.
Step 3: Add Cheese and Seasoning
Remove the saucepan from the heat. Stir in 1 cup shredded Gruyere cheese, ½ cup grated Parmesan cheese, and 1 teaspoon fresh thyme. Keep stirring until the cheese is all melted. Season with salt and pepper to your taste.
Step 4: Layer the Gratin
Now for the fun part! Arrange half of your sweet potato slices in the bottom of your baking dish. Pour half of the cheese sauce over them. Then, layer the remaining potato slices on top and pour the remaining sauce over everything.
Step 5: Bake to PERFECTION!
Sprinkle the top with the last ½ cup Gruyere cheese. Bake for 45-55 minutes, or until the top is golden brown and bubbly. Let it cool for about 10 minutes before you serve it.
Tips for the Best Sweet Potato Au Gratin
Here are a few of my favorite tricks to make sure your gratin turns out amazing every single time!
- Slice Evenly. Use a mandoline for potatoes that are the same thickness. This helps them cook at the same rate.
- Use Fresh Cheese. Grate your own cheese! It melts so much better than the pre-shredded kind and tastes better, too.
- Don’t Boil the Cream. Just gently simmer your cream. Boiling it can make the sauce separate, and nobody wants that.
- Let It Rest. Let the gratin sit for about 10 minutes after baking. This helps the sauce set up nicely.
- Pick Good Potatoes. Look for sweet potatoes that are firm and don’t have any soft spots. Better potatoes make a better dish.
- Fresh Herbs are Key. Fresh thyme brightens up the flavor. You can use dried, but fresh is always best.
Variations and Substitutions
Want to mix things up a bit? Here are some fun ideas to make this dish your own special creation!
- Try Different Cheeses. Feel free to swap Gruyere with white cheddar, smoked gouda, or even a mix of your favorites.
- Add Some Spice. Put a little kick in your dish! Add a pinch of cayenne pepper or nutmeg to the cream sauce.
- Use Other Root Veggies. You can mix in some thinly sliced russet potatoes, parsnips, or celery root for a new flavor.
- Make it Herby. Add some fresh rosemary or sage along with the thyme. This will give it an even cozier taste.
- Add a Topping. For a little crunch, sprinkle some toasted breadcrumbs or crispy bacon on top before you serve it.
Make-Ahead and Storage Tips
This dish is a lifesaver for busy days! You can assemble the entire gratin a day ahead of time. Just cover it tightly with plastic wrap and keep it in the fridge. When you are ready, take it out of the fridge for 30 minutes before baking as directed. You might need to add 5-10 extra minutes to the baking time.
Got leftovers? Lucky you! Store them in an airtight container in the fridge for up to 4 days. To reheat, just pop a slice in the microwave or warm it in the oven until it’s heated through.
Recipe FAQs
Can I use regular potatoes?
Yes, you sure can! Russet or Yukon Gold potatoes would be a great substitute. The baking time should stay about the same.
Is it possible to make this dairy-free?
You can try using full-fat coconut milk and your favorite dairy-free cheese. The texture might be a little different, but it should still be tasty.
Should I peel the sweet potatoes?
I like to peel them for a smoother texture. But if you like the skins, you can leave them on! Just make sure to scrub them well first.
What should I do if the top gets too brown?
If the top starts to get too dark before the potatoes are cooked, just loosely cover the dish with a piece of aluminum foil.
Can I freeze sweet potato au gratin?
Yes! You can freeze it before or after baking. Wrap it well and freeze for up to 3 months. Thaw it in the fridge overnight before baking or reheating.
What to serve with sweet potato au gratin?
This dish goes great with roasted chicken, baked ham, or a juicy steak. It’s also lovely with a simple green salad on the side.
Why is my gratin watery?
This can happen if the cream sauce is too thin or if the potatoes release a lot of liquid. Make sure your sauce simmers and thickens a bit.
Cheesy Sweet Potato Au Gratin
Ingredients
- 3 pounds sweet potatoes (peeled and thinly sliced 1/8 inch)
- 1 ½ cups heavy cream
- 1 ½ cups shredded Gruyere cheese (divided)
- ½ cup grated Parmesan cheese
- 4 tablespoons butter (divided)
- 2 cloves garlic (minced)
- 1 teaspoon fresh thyme leaves
- salt and black pepper to taste
Instructions
- Preheat oven: Set your oven to 400°F (200°C). Grease a 9×13 inch baking dish with 1 tbsp of butter.
- Make cream Ssuce: Melt 3 tbsp of butter in a saucepan over medium heat. Cook 2 minced garlic cloves for 1 minute. Stir in 1 ½ cups of heavy cream and simmer gently.
- Add cheese: Remove the pan from the heat. Stir in 1 cup of Gruyere, ½ cup of Parmesan, and 1 tsp of thyme until smooth. Season with salt and pepper.
- Layer potatoes: Arrange half of the sweet potato slices in the prepared dish. Pour half of the creamy sauce over the top.
- Add final layer: Layer the remaining sweet potato slices on top. Pour the rest of the sauce over everything. Sprinkle with the remaining ½ cup of Gruyere.
- Bake and serve: Bake for 45-55 minutes, until the top is golden and the potatoes are tender. Let it rest for 10 minutes before serving. ENJOY!
Notes
- A mandoline slicer is highly recommended for even slices.
- Grating your own cheese will give you the creamiest results.
- Let the gratin rest before serving so the sauce can set.
- Feel free to add a pinch of nutmeg for extra warmth.
- Store any leftovers in the fridge for up to 4 days.
