Name: Au Gratin Potatoes
Prep time: 20 min
Cook time: 1 h
Total time: 1 h 20 min
Yield: 8
Cuisine: French inspired
Ingredients: 2 pounds Yukon gold potatoes, sliced 1/8 an inch thick; 1 small to medium yellow onion, sliced 1/8 an inch thick; 3 tablespoons salted butter; 4 cloves garlic, minced; 3 tablespoons all purpose flour; 2 cups whole milk; 1/2 cup chicken broth; 1 teaspoon salt, plus more to taste; 1/4 teaspoon black pepper, plus more to taste; 1/4 teaspoon nutmeg; 1 tablespoon Dijon Mustard; 6oz gruyere cheese, shredded and divided; 4oz parmesan cheese, shredded and divided; 2 teaspoons fresh thyme, plus more for serving

These Cheesy Au Gratin Potatoes are the perfect side dish. Perfectly tender potatoes are cooked in a flavorful cheesy cream sauce. You’ll love them!

Cheesy Au Gratin Potatoes

What is better than potatoes swimming in a cheese sauce?! Nothing! Haha, maybe I’m being dramatic but if you’re a potato lover (like this girl) then you understand.

These Cheesy Au Gratin Potatoes are a combination of thinly sliced potatoes, perfectly cooked in a flavorful creamy cheese sauce. The potatoes are topped with even more cheese and baked until golden brown.

If you’re looking for a delicious and decadent side dish that everyone will love then these potatoes are perfect for you!

Watch How to Make This Recipe

What’s the Difference Between Potatoes Au Gratin and Scalloped Potatoes?

If you grew up like me, then you might have used potatoes au gratin and scalloped potatoes interchangeably but, surprisingly, they’re actually two different recipes.

The main difference between the two dishes is the cheese. Scalloped potatoes are a much simpler dish than au gratin potatoes and there is no cheese in between the layers of the potatoes. Instead the potatoes are simply baked in a cream sauce. Alternatively, au gratin potatoes are made with a creamy cheese sauce and topped with cheese as well.

The Best Potatoes to Use

The trick to perfect au gratin potatoes is using the right potato. You want to avoid less starchy, waxier potatoes for this dish (like red potatoes) and opt for starchier potatoes instead. Russet potatoes or Yukon gold are both great options. I personally love using Yukon golds for this recipe because you don’t have to peel them!

Au Gratin Ingredients

Potatoes: we’re using Yukon gold potatoes for this recipe. They’re starchy enough and no peeling required.

Yellow Onion: thinly sliced yellow onion is layered in between the potatoes to add extra flavor.

Butter: unsalted butter is the start of the creamy cheese sauce.

Garlic: you’ll need plenty of fresh garlic for these delicious potatoes.

Flour: all-purpose flour helps to thicken the cream sauce.

Milk: you’ll need whole milk to make this recipe. If you need to substitute the milk for something dairy free I would recommend using canned coconut milk.

Chicken Broth: I usually grab low-sodium chicken broth when cooking so that I can better control the salt level in the dish.

Nutmeg: a classic ingredient in any au gratin dish.

Dijon Mustard: this adds just the right flavor to the creamy au gratin cheese sauce.

Cheese: for this recipe we’re using a combination of gruyere and parmesan cheese.

Thyme: plenty of fresh thyme is running through the cheese sauce and then we’ll add a bit on top before serving.

Helpful Kitchen Tools

mandolin slicer – this is the easiest and best way to evenly slice all of the potatoes you need for this dish.
casserole dish – you’ll need a 3.5 quart or 9×13 inch casserole dish to make this recipe.
saucepan – to make the cheese sauce, that covers the potatoes you’ll also need a large saucepan.
whisk – this helps to whisk in the cheese for the perfect creamy sauce.
measuring cups / measuring spoons – to get just the measurement for each of your ingredients.
box grater – this is key for shredding your cheese. You could also use a food processor with a shred attachment if you prefer.

How to Make Au Gratin Potatoes

Step One: Preheat oven to 375 degrees.

Step Two: Prep the potatoes and onions by slicing with a mandolin set to 1/8 inch thick. Season the potatoes and onions with 1/2 teaspoon of salt and 1/4 teaspoon black pepper. Toss until well combined and then transfer to lightly greased 3.5 quart round casserole dish or 9×13 inch baking dish.

Step Three: Heat a large saucepan over medium heat. Add the butter and let melt then add the minced garlic. Sauté the garlic for one minute until fragrant. Next, whisk in flour and cook for another 1-2 minutes.

Step Four: Next, slowly whisk in the whole milk and chicken broth, around 1/4 cup at a time, whisking continuously as you pour it in. Stir in the salt, pepper, nutmeg and Dijon Mustard and let cook for another 2 to 4 minutes until the sauce has started to thicken, whisking constantly.

Step Five: Remove the sauce from the heat and stir in 3 oz shredded gruyere cheese and 2 oz shredded parmesan cheese until melted and well combined. Add in the fresh thyme and season to taste with additional salt and pepper.

Step Six: Pour the cheese sauce evenly over top of the potatoes in the casserole dish.

Step Seven: Bake the potatoes at 375 degrees for 50 to 60 minutes covered with aluminum foil, or a lid, until the potatoes are tender.

Step Eight: Remove the covering and top the au gratin with remaining shredded cheese and continue baking for additional 20-25 minutes until the potatoes are golden brown on top. Top with a bit of fresh thyme and chopped parsley before serving.

What to Serve with Au Gratin Potatoes

How to Store

Store: You can store the au gratin potatoes in an air-tight container in the fridge for 3-4 days after baking.

Reheat: The best way to reheat these potatoes is in the oven. Start by letting the potatoes come to room temperature and then reheating in a 375 degree oven for 15-20 minutes, covered until hot. If you’re really in a pinch you can of course use the microwave.

More Delicious Holiday Sides

I hope you give these Cheesy Au Gratin Potatoes a try! If you do give this recipe a try, let me know!

Leave a comment with a star rating below. You can also snap a photo & tag @allthehealthythings on INSTAGRAM. Your reviews and ratings help support All the Healthy Things and make it possible for me to continue to create the recipes you trust and love.

Au Gratin Potatoes

5 Stars 4 Stars 3 Stars 2 Stars 1 Star

Author: Ashlea Carver
Prep Time: 20 minutes
Cook Time: 60 minutes
Total Time: 1 hour 20 minutes
Yield: 8 1x
Category: sides
Method: baking
Cuisine: French inspired
Diet: Vegetarian

Print Recipe

Author: Ashlea Carver
Prep Time: 20 minutes
Cook Time: 60 minutes
Total Time: 1 hour 20 minutes
Yield: 8 1x
Category: sides
Method: baking
Cuisine: French inspired
Diet: Vegetarian

Ingredients

2 pounds Yukon gold potatoes, sliced 1/8 an inch thick
1 small to medium yellow onion, sliced 1/8 an inch thick
3 tablespoons salted butter
4 cloves garlic, minced
3 tablespoons all purpose flour
2 cups whole milk
1/2 cup chicken broth
1 teaspoon salt, plus more to taste
1/4 teaspoon black pepper, plus more to taste
1/4 teaspoon nutmeg
1 tablespoon Dijon Mustard
6oz gruyere cheese, shredded and divided
4oz parmesan cheese, shredded and divided
2 teaspoons fresh thyme, plus more for serving

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Method

Preheat oven to 375 degrees.
Prep the potatoes and onions by slicing with a mandolin set to 1/8 inch thick. Season the potatoes and onions with 1/2 teaspoon of salt and 1/4 teaspoon black pepper. Toss until well combined and then transfer to lightly greased 3.5 quart round casserole dish or 9×13 inch baking dish.
Make the Sauce: Heat a large saucepan over medium heat. Add the butter and let melt then add the minced garlic. Sauté the garlic for one minute until fragrant. Next, whisk in flour and cook for another 1-2 minutes.
Next, slowly whisk in the whole milk and chicken broth, around 1/4 cup at a time, whisking continuously as you pour it in. Stir in the salt, pepper, nutmeg and Dijon Mustard and let cook for another 2 to 4 minutes until the sauce has started to thicken, whisking constantly.
Remove the sauce from the heat and stir in 3 oz shredded gruyere cheese and 2 oz shredded parmesan cheese until melted and well combined. Add in the fresh thyme and season to taste with additional salt and pepper.
Pour the cheese sauce evenly over top of the potatoes in the casserole dish.
Bake the potatoes at 375 degrees for 50 to 60 minutes covered with aluminum foil, or a lid, until the potatoes are tender.
Remove the covering and top the au gratin with remaining shredded cheese and continue baking for additional 20-25 minutes until the potatoes are golden brown on top. Top with a bit of fresh thyme and chopped parsley before serving.