Potatoes Au Gratin is a classic side dish featuring thin slices of potato layered with a rich, creamy cheese sauce, then baked until lightly crisp on the edges. Make it for a weeknight dinner or double the recipe for a crowd!
Potatoes au gratin—sometimes also known as au gratin potatoes—is a classic French recipe that’s become a favorite of home cooks in the United States. Now, don’t get these confused with scalloped potatoes! I love those too, but scalloped potatoes are traditionally made with a simple cream sauce seasoned with salt and pepper, while potatoes au gratin are made with cheese. Lots of cheese!
Easy Potatoes Au Gratin Recipe
Of course, there are many variations of potatoes au gratin, but the one I share below is pretty much the classic version, which uses a heavy cream-based sauce and gruyere cheese. If you’ve ever made homemade mac and cheese with from-scratch cheese sauce, you already have the skills you need to make the sauce for your potatoes au gratin. You start with a roux, then add the cream, followed by the cheese.
If you’ve tried making scalloped potatoes in the past and the sauce separated, you can feel confident knowing that this is far less likely to happen with potatoes au gratin. The heavy cream, roux, and dry mustard all help keep the sauce from curdling in the oven.
See the recipe card below this post for ingredient quantities and full instructions.
- Russet potatoes – They need to be thinly sliced, so use a mandoline slicer if you have one.
- Heavy cream – Don’t try to lighten up this recipe by using milk instead, because it will make your sauce more prone to curdling.
- Gruyere cheese
- Salt + pepper
- Dry mustard
- Russet potatoes – You can use sweet potatoes or Yukon gold potatoes instead.
- Gruyere – Parmesan, Swiss, cheddar, or any other cheese with an assertive flavor can be swapped for the gruyere, or you can use a combination of cheeses.
How to Make Potatoes Au Gratin
1. Prepare: Preheat the oven to 350ºF and grease a 1.5-quart casserole dish with butter or nonstick cooking spray.
2. Make the Sauce: Melt the butter in a small saucepan, then whisk in the flour. Once it’s golden brown, slowly whisk in the cream. Cook the sauce on low until it’s smooth and just comes to a boil; continue to whisk until it’s thick, then stir in the salt, pepper, and dry mustard. Whisk in a cup of the cheese.
3. Assemble: Place half of the sliced potatoes in the prepared casserole dish, then pour half of the cheese sauce on top. Add another layer of potatoes, followed by another layer of cheese. Top with the remaining cheese and sprinkle the top with paprika.
4. Bake: Bake the potatoes uncovered for an hour, or until they’re tender and just beginning to brown along the edges.
Hint: You can turn on the broiler in the last few minutes of cooking time to make the top layer crispy and browned.
- Hasselback – You can arrange the potatoes Hasselback-style (standing up and packed into the dish tightly) instead of laying them flat in the baking dish.
- Herbed – Add dried or fresh thyme or rosemary to the sauce before pouring it over the potatoes.
- Garlicky – Add minced garlic with the flour when you’re making the cheese sauce.
Gruyere is the traditional cheese used for making potatoes au gratin, but feel free to experiment with other types of cheese.
Yes, you can assemble potatoes au gratin and refrigerate them for up to a day before baking them.
It’s important that the potatoes are all sliced to the same thickness, otherwise, you’ll have some that are mushy and others that are hard and taste raw when you pull the gratin out of the oven.
More Potatoe Recipes To Enjoy
Potatoes Au Gratin
- 4 cups thinly sliced russet potatoes
- 3 tbsp butter
- 3 tbsp flour
- 1 1/2 cups heavy cream
- 1 1/2 cups gruyere cheese divided
- 1 tsp salt + pepper
- 1 tsp dry mustard
- Preheat the oven to 350 degrees.
- In a small sauce pan, melt butter. Once melted add flour with a fork – whisking together.
- Next, whisk in milk.
- Cook sauce on low until smooth and boiling, whisking until thickened.
- Add in salt, pepper , and dry mustard and stir well.
- Reduce heat to low and stir in 1 cup of the cheese.
- Place a half of the sliced potatoes in a lightly greased 1.5 quart casserole dish (8×8 or 9×9 will work)
- Pour half of the cheese sauce over potatoes.
- Add a second layer of potatoes and the rest of the cheese sauce to the top of that layer
- Sprinkle the remaining 1/2 cup of cheese on top.
- Sprinkle the top with paprika.
- Bake at 350 degrees, uncovered for 1 hour.