Potatoes Au Gratin sounds fancy, but it’s easy to make and a delicious way to prepare potatoes!
In this gratin recipe, potatoes and onions are thinly sliced and baked in a rich cheesy sauce until bubbly and golden brown.
They’re perfect for Sunday supper or to serve with any holiday meal!
Scalloped potatoes vs. Potatoes au Gratin
The difference is the cheese.
Technically, gratin is defined as “covered with breadcrumbs or cheese”, and scalloped refers to “baked with milk or a sauce”. However, many people still refer to gratin potatoes as scalloped potatoes.
This Potatoes au Gratin recipe is similar to scalloped potatoes but with a cheesy sauce instead of a white sauce. Either are great with Sunday supper or next to baked ham or meatloaf.
Ingredients for Potatoes au Gratin
- Potatoes: The best potatoes for potatoes au gratin are waxy potatoes like red-skinned or Yukon gold. They hold their shape well, and because they’re thin-skinned, they do not require peeling (extra bonus!).
- Note: While russet potatoes or baking potatoes will work and taste good in this recipe, they’re more starchy and may fall apart once cooked—they’re more suited to mashed potatoes.
- Onion: Thinly sliced onion adds flavor to these potatoes. For a milder flavor, cook the onion in butter first or replace it with 1 teaspoon of onion powder in the sauce.
- Cheese: I use cheese with a lot of bold flavors in this recipe, including cheddar, parmesan, and Gruyere.
- Option: Gruyère cheese adds a rich flavor to the cheese sauce but can be replaced with provolone or Swiss for a similar flavor!
- Sauce: Butter and flour create a roux to thicken this sauce, and I use milk as the base. It’s plenty rich enough with all of the cheese.
How to make Potatoes Au Gratin
Here is a quick overview of the steps for potatoes au gratin.
- Prep: Thinly slice the potatoes and onions.
- Sauce: Make the cheese sauce in a saucepan on the stove.
- Assemble: Stack the potato slices and onions in little piles and then stand them on their sides in the casserole dish.
- Bake: Bake until the potatoes are tender and the sauce is bubbly.
Find the full detailed recipe below.
Holly’s Pro Tips
- For easy prep and even thin slices, use an inexpensive mandoline. You can find them for under $20, and it saves a lot of time.
- Pre-shredded cheese will work in this recipe, however the sauce will be smoother if you shred cheese from a block.
- If swapping the cheese, make sure you use those with bold flavors.
- If you’re short on time, set the potatoes and onions in the dish as directed and cover with plastic wrap. Microwave on full power for about 10 minutes (it will be hot when removing the plastic wrap). Add the cheese sauce and bake as directed below for about 45-55 minutes. Just as delicious… but a little bit quicker!
How to Make Potatoes au Gratin Ahead of Time
This dish can be made 24 hours in advance. Ensure the potatoes are completely covered in the sauce—any exposed bits of potatoes will discolor slightly. Cover tightly with plastic wrap and refrigerate.
Remove from the fridge at least 30 minutes before baking. You may need to add 10 to 20 minutes to the baking time.
While we often eat these as a side, I sometimes make Potatoes au Gratin with ham by including slices or diced leftover ham (from our favorite crock pot ham) before baking.
Did you make this Potatoes au Gratin recipe? Leave us a rating and a comment below.
Potatoes Au Gratin
Ingredients
- 2 ½ pounds red potatoes
- 1 onion thinly sliced
- 3 tablespoons butter
- 3 tablespoons all-purpose flour
- 1 teaspoon dry mustard powder
- 2 cups milk
- 1 cup shredded cheddar cheese
- ½ cup shredded gruyere cheese
- ¾ teaspoon salt divided
- ½ teaspoon black pepper divided
Instructions
- Preheat oven to 400°F.
- Wash potatoes and slice into ⅛" thin slices. Slice onion as thin as possible.
- Season the potatoes and onions with ½ teaspoon of salt and ¼ teaspoon of pepper. Toss well to evenly coat. Layer potatoes and onions into little stacks. Place stacks on their side in a greased 2.5qt to 3qt casserole dish.
- Melt butter and flour in a saucepan and cook 2 to 3 minutes. Add mustard powder, ¼ teaspoon salt, ¼ teaspoon pepper and milk. Whisk over medium heat until thick and bubbly. Remove from heat and stir in cheeses until melted.
- Pour the cheese sauce over the potatoes, gently separating them to allow the sauce to seep between the layers. Cover with foil (sprayed with cooking spray) and bake 60 minutes.
- Remove foil and bake an additional 20 to 30 minutes or until lightly browned and potatoes are cooked. Cool 15 minutes before serving.
Video
Notes
Nutrition Information
Nutrition information provided is an estimate and will vary based on cooking methods and brands of ingredients used.
Course Side Dish
Cuisine American, French© SpendWithPennies.com. Content and photographs are copyright protected. Sharing of this recipe is both encouraged and appreciated. Copying and/or pasting full recipes to any social media is strictly prohibited. Please view my photo use policy here.
So this is the fourth or fifth time I’ve made this recipe. Each time I’ve changed it slightly. Easter, I think I had it perfect. I substituted Scallions for onions (sweeter) and used 1 1/2 cups Gruyere and 1/2 cup finely grated Parmesan; finally, I substituted one of the cups of milk with buttermilk and added a tablespoon of Garlic and a teaspoon of Italian herbs. It’s absolutely amazing. It has a bit more flavor than the basic recipe, but is not overpowering at all.
this recipe is amazing! Thank you for sharing!
When preparing these a day in advance advance, do you bake the dish after you pour the cheese sauce on since the potatoes are now warmed from the cheese sauce and simply reheat the next day, or cover the raw potatoes with the hot cheese sauce, immediately refrigerate and then bake the next day? Thank you!
When making in advance, as long as the potatoes are completely covered in the sauce you do not need to bake it first. I generally pour the sauce overtop and cool slightly (while I clean up) before refrigerating. Remove from the fridge at least 30 minutes before baking adding 10 to 20 minutes to the baking time in the recipe.
Made this once and making again tonight my boyfriend requested is as I’ll be out of town and he wanted this dish to snack on. First time around was a success so will this! Thank you!
Thanks for this recipe. I cooked baked potatoes using your recipe for the oven. I then used this recipe and added a can of cream of mushroom soup for the sauce and threw in some crawfish. We served it on top of the baked potatoes. It was absolutely delicious. It was served on the side of your braised thighs with mushrooms.
I 4x the recipe for a 10lb bag of potatoes and it turned out perfect.
brilliant
Thank you, Kevin. I am glad you enjoyed it.
I thought at first it was a little time consuming but now I don’t mind it at all, worth the time!! It’s so delicious. I’ll be making it many more times I’m sure ❤️❤️❤️
this is wonderful, I added some carrots, cauliflower and broccoli.. great dinner!!
I made these exactly as written, and they were amazing! Everyone commented on how good they were, and there was none left.
I made this for a 50s dinner party. I had never made this dish before. I was a big success. I forgot the mustard. And next time I will make more cheese sauce.
excellent
very nice l add a little cheese
Amazing recipe!!!
These tasted bland. I used Yukon gold potatoes and omitted the onions. I added rosemary to the cheese sauce for some extra flavor. I did shred my own cheeses as well. Not sure what happened.
These potatoes are fantastic. My family wanted a potato dish for Easter and I chose this one after searching online. I am not crazy about potatoes but I had two helpings.
I used a combination of Cheddar , Swiss and Parmesan . I used pre shredded- my brand doesn’t have any additives so no problems with melting .
Can I use heavy cream instead of milk?
I haven’t tried it so can’t say for certain but it will likely be a bit thicker with heavy cream. You could substitute half with low sodium broth as well. If you do use heavy cream and it’s too thick, you can thin it out with a bit of water or broth. Let us know how it goes!
Made this today. It was great.i included some chopped bell pepper.