This Potatoes Au Gratin Recipe is made with delicious layers of thinly sliced potatoes smothered in homemade cream sauce, shredded cheese, and is baked until tender, golden, and bubbly. The ultimate comfort food, enjoy these creamy and comforting Au Gratin Potatoes with friends and family at your next holiday or family gathering.
The Best Cheesy Potatoes Au Gratin
I have enjoyed these thinly sliced potatoes – or some version of them – on every major holiday since the year I was born. Christmas, Thanksgiving, Easter, these potatoes are always a favorite and one of the first things to disappear from the table.
Cheesy and extra creamy, potatoes au gratin is a classic potato casserole and the ultimate comfort food. Definitely not for anyone counting calories, I highly recommend skipping past the nutritional information and embrace every single bite of these beautiful cheesy potatoes.
Anyway, let’s start from the beginning.
What are au gratin potatoes?
Potatoes au gratin is a classic potato side dish made with thinly sliced potatoes covered in a rich and creamy sauce that has been thickened with a roux. The roux (a mixture of butter and flour) helps make the cream sauce extra silky and prevents the milk from curdling. Cheese is added and the whole thing is baked. It is pure, delicious, comfort food, and loved by everyone.
What’s the Difference Between Au Gratin Potatoes and Scalloped Potatoes?
Let’s take a quick sec to chat about the difference between potatoes au gratin and scalloped potatoes.
- Potatoes au gratin: the potatoes are traditionally cut into thinner rounds, approximately 1/8-inch thick, cheese is added to the recipe (this is the most defining difference), and breadcrumbs are often sprinkled over the top for added crunch.
- Scalloped potatoes: the potatoes are cut into thicker rounds, approximately 1/4-inch thick. The potatoes are layered and baked in a cream sauce without the addition of cheese or breadcrumbs.
Check out this recipe for scalloped potatoes!
Ingredients in Potatoes Au Gratin
The ingredients needed to make this easy potato dish include,
- All-Purpose Flour
- Salt and Black Pepper
- Yellow Onion (optional)
The butter and milk are responsible for making the roux. The roux is what stabilizes and helps prevent the milk from curdling at such high temperatures in the oven. It also helps thicken your sauce.
How much salt is needed? This will vary from one cook to another, but keep in mind that, even with cheese and cream, potatoes will taste pretty bland. I recommend adding at least 1-2 teaspoons salt.
Best melting cheese for potatoes au gratin?
- Gruyere cheese – a flavorful medium-hard cheese that is great for melting. You’ll often find it in mac n cheese and French onion soup.
- Cheddar cheese – I prefer adding sharp cheddar cheese as it has better flavor.
- Parmesan cheese – not a good melting cheese, but the flavor is great.
Best Potatoes for Au Gratin Potatoes
There are two main types of potatoes, waxy potatoes vs starchy potatoes.
Waxy potatoes, which include Yukon gold potatoes and red potatoes, hold their shape even after cooking and are less likely to turn mushy. Starchy potatoes, which include russet potatoes, are fluffy, light, and typically fall apart easier.
For this recipe, I used russet potatoes. Yukon gold would have been an equally delicious option.
Learn more: Waxy vs. Starchy Potatoes: Which One to Use?
What’s the Best Way to Slice Potatoes for Au Gratin?
The easiest way to thinly slice potatoes is by using a mandolin slicer. You can find them available in stores and online to fit all budgets. Make sure you purchase one with a handguard (please, learn from my mistake!) and consider wearing special cut-resistant gloves as an extra precaution.
You may also use a sharp knife, but unless you have some serious knife skills, you may have a really hard time getting your potatoes thin enough. That said, my dad never used a mandolin slicer so I know it’s possible!
How to make Potatoes Au Gratin
1. Preheat your oven to 350 degrees F. and grease a large baking dish with non-stick cooking spray. Set aside.
2. Thoroughly wash each potato under cold water and dry thoroughly. Use a sharp knife or a mandoline slicer to slice potatoes into thin slices (approximately 1/8-inch). Transfer the sliced potatoes to a large bowl filled with cold water to prevent discoloration (they will turn into a reddish-orange color). Repeat until all potatoes have been sliced.
3. To make the bechamel sauce, melt butter in a large saucepan over medium heat. Gradually whisk in the flour, creating a thick, evenly combined, paste. Still whisking, slowly add the milk, salt, and pepper. Continue to whisk until completely combined. Bring just to a boil and reduce heat to low. Simmer for 2-3 minutes, or until the sauce has thickened slightly.
4. Remove from heat and stir in 1 cup of the cheddar cheese and half of the Gruyere.
5. Drain the potato slices from the cold water bath and dry thoroughly with a paper towel. Add the potatoes and onion to the prepared sauce and gently mix to coat.
6. Transfer potatoes to the prepared baking dish and pour any remaining creamy cheese sauce over the top.
7. Tent with foil and transfer to the oven. Bake for 45 minutes before uncovering and baking for an additional 30 minutes. Remove from the oven, sprinkle with the remaining cheese, and continue to cook for an additional 45-60 minutes, or until cheese is melted, golden brown and potatoes are tender.
Tips and Tricks
- How you arrange the potato slices is up to you. Layer your potatoes in overlapping layers or long columns (like stacked poker chips) as I did. The total cooking time will be the same. Keep in mind that stacked columns are more time consuming (but quite pretty) and, results in crispy edges on the top (which you may or may not enjoy).
- Remember to cover your baking dish with foil for the first half of cooking. This will help protect the top of your potatoes from the heat.
- Make your potatoes au gratin super garlicky by adding a few minced garlic cloves to the bechamel sauce.
- Slice your potatoes into equally thick rounds. This helps ensure even cooking.
- This is a slow-cooking recipe. There will be a lot of sauce and a lot of potatoes, but the sauce will reduce and the potatoes will bake. It will all be worth it – promise!
- To make this recipe gluten-free, use gluten-free all-purpose flour.
- For best results, use whole milk or half 2% milk with heavy cream or half-and-half.
Can you Freeze Potatoes Au Gratin?
I have not tried freezing au gratin potatoes personally, so I can’t give you my own personal opinion on the results. Additionally, after digging around the internet, I found mixed reviews. That said, here’s what I found,
- If you plan on freezing, it’s recommended that you use a waxier potato (Yukon gold or red potato) compared to starchy potatoes (russet potatoes). Starchy potatoes result in a grainer mixture after thawing.
- Have reasonable expectations. In other words, it will not be the same as when you first made it. The cheese mixture will likely separate a little and you will probably have to do some gentle stirring.
- Make sure to cook your potatoes before freezing, otherwise, they will turn black.
More Potato Recipes,
If you try making potatoes au gratin recipe, please leave me a comment and let me know! I always love to hear your thoughts.
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Potatoes Au Gratin Recipe
- 5 pounds Russet or Yukon Gold Potatoes (thinly sliced (approximately ⅛-inch))
- 4 tbsp butter
- 4 tbsp all-purpose flour
- 2 tsp salt
- 1/2 tsp pepper
- 2 cups milk ((2% or whole milk))
- 2 cups cheddar cheese (shredded)
- 1 cup Gruyere cheese (shredded)
- 1 small onion (thinly sliced or diced)
- Preheat. Preheat oven to 350 degrees F. and grease a large baking dish. Set aside.
- Prepare potatoes. Scrub potatoes under cold water with a vegetable brush. Use a mandolin to slice potatoes into evenly sliced rounds (approximately 1/8-inch). Set potatoes aside into a large bowl filled with cold water to prevent discoloration.
- Make sauce. Melt the butter in a large saucepan over medium-high heat. Gradually whisk in the flour, creating a thick, evenly combined, paste. Still whisking, slowly add the milk, salt, and pepper. Continue to whisk until completely combined. Bring to a boil and reduce heat too low. Simmer for 2-3 minutes, or until the sauce has thickened slightly. Remove from heat and stir in 1 cup of the cheddar cheese and half of the Gruyere cheese.
- Add the potatoes and onion. Drain the potatoes from the cold water bath and dry thoroughly with a paper towel. Add the potatoes and onion to the prepared sauce and mix to coat.
- Assemble. Transfer potatoes to the prepared baking dish and pour any remaining sauce over the top.
- Bake. Cover with foil and transfer to the oven. Bake for 45 minutes before uncovering and baking for an additional 30 minutes. Remove from the oven, sprinkle with the remaining cheese, and continue to cook for an additional 45-60 minutes, or until cheese is melted and potatoes are tender.
- You may choose to layer your potatoes in overlapping rows (more traditional) or long columns (like stacked poker chips) as I did. The cooking time will be the same.
- To make this recipe gluten-free, use gluten-free all-purpose flour.
- Check out the full post for all my tips and tricks!
(Nutrition information provided is an estimate and will vary based on cooking methods and specific brands of ingredients used.)