Au Gratin Potatoes

Au Gratin Potatoes are thinly sliced potatoes, covered in a creamy cheese sauce and then topped with more cheese and baked in the oven until they are soft with a crispy, cheesy crust! It’s the perfect side dish for a holiday meal or really any meal for that matter! 

Growing up, I loved it when my mom would fix cheesy potatoes (aka-Au Gratin Potatoes!)  We typically had them when we had a ham dinner, with buttery pull-apart rolls and roasted veggies! But we never had leftovers because everyone loved this cheesy potato casserole with its crispy cheesy crust! 

Au gratin potatoes on dish

Au Gratin vs Scalloped Potatoes

You may feel intimidated by the words, Au Gratin, but don’t be! In French, Au Gratin means “by grating” or “with a crust.” This potato recipe is au gratin because we top the thinly sliced potatoes with an extra layer of cheese before baking, giving it a delicious cheesy crust! 

Many people confuse au gratin potatoes with scalloped potatoes, and for awhile so did I! They both consist of thinly, round sliced potatoes, baked in a casserole dish. And both are extremely yummy!

The difference is that scalloped potatoes are traditionally cut thicker and covered in a cream sauce, infused with garlic and fresh herbs. And au gratin potatoes are thinner, covered in a cheese sauce and then topped with more cheese or bread crumbs before being baked.  

Thin sliced potatoes in baking dish

How to Make Au Gratin

When making Au Gratin Potatoes, I like to use russet or yukon gold potatoes, because they are higher in starch and therefore able to absorb more of the sauce and they hold their shape well! 

The key is to slice your potatoes thin enough to fully cook (no one likes a crunch potato!) but not to think that they fall apart and become mushy. I aim to cut my potatoes so they are 1/4 inch thick.

I prefer to use my mandoline slicer to cut my potatoes. The mandoline slicer is nice because your slices are more consistent and it is faster! But if you don’t have one, don’t fret because you can also use your regular knife and cutting board! 

And finally, decide what type of cheese you want to use. Traditionally Au Gratin Potatoes use Gruyere cheese. It can be expensive and hard to find. If I can find it, I like to mix it with cheddar. However, most of the time I use a blend of cheddar and Colby jack! 

  Au gratin potato side dish picture

Storing + Tips

PREP: I love making these potatoes for Thanksgiving or Christmas and the best part is you can prep them the day before! Follow the instruction all the way up to the point of topping your potatoes with the final layer of shredded cheese! Then cover and refrigerate for up to a day. 

When you are ready to bake, let them sit on the counter for 20 minutes prior to baking! Don’t forget to top with the final layer of cheese!

STORING: Once baked, your Au Gratin Potatoes will stay good in an airtight container for 3-5 days in your refrigerator. You can also freeze them, just let them thaw in the refrigerator the day before you plan on eating them! 

REHEAT: To reheat you can nuke them real quick in the microwave or cover with foil and reheat in the oven at 350 degrees for 20-30 minutes.

Cheesy au gratin potatoes in baking dish

As you can see, there is no need to be intimidated by Au Gratin Potatoes! They are simple to make but bursting with flavor! Give them a try and let us know what you think. We have a feeling you’ll love them. 

For more potato recipes:

Au Gratin Potatoes

4.94 from 15 votes
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Prep Time: 20 mins
Cook Time: 1 hr 30 mins
Servings: 8
Author: Natalie
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  • 6 medium russet potatoes, rinsed, peeled, and cut into 1/4-inch thick slices
  • 2 tbsp. unsalted butter
  • 1/2 c. diced yellow onion
  • 2 cloves garlic, minced
  • 2 tbsp. all-purpose flour
  • 2 c. half & half
  • 1 1/2 tsp. kosher sea salt
  • 1/4 tsp. ground black pepper
  • 1 1/2 c. grated cheddar and colby jack cheese
  • 1 tbsp. sliced chives (optional)


  • Preheat oven to 350 degrees. Lighty spray or butter a 9x13-inch baking dish. Arrange potatoes by fanning them in three lines across the pan. Set aside.
  • In a medium saucepan set over medium heat, add the butter. Once melted add the onion and saute for 3-5 minutes or until tender. Add the garlic and continue cooking for 1 additional minute.
  • Whisk in the flour, cook until lightly golden in color, then slowly pour in the half & half, whisking until all of the liquid has been incorporated. Whisk in salt and pepper.
  • Pour mixture over the potatoes. Top with cheese.
  • Cover with aluminum foil and bake for 45 minutes. Remove the foil and continue baking for 15-30 minutes or until golden brown and potatoes are fork-tender.
  • Let cool for 15 minutes before serving. Top with fresh chives, if desired.