Potatoes au gratin is the perfect side dish for Sunday supper or as a make-ahead holiday side dish. Tender layers of potatoes and onions are baked in a rich, creamy, cheesy sauce until hot, bubbly, and golden.
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Holly’s Recipe Highlights
This recipe makes creamy potatoes, similar to scalloped potatoes but loaded with rich cheesy flavor. They are the perfect dish next to a baked ham, roast beef tenderloin or pork tenderloin.
- Flavor: Creamy, cheesy, and comforting with a golden, slightly crispy top that makes every bite irresistible.
- Why it works: A cooked roux thickens the sauce so it coats the potatoes instead of pooling thin at the bottom.
- Recommended Tools: To save time on prep and make even and thin potato and onion slices, use a mandoline or the side of a box grater.
- Time-Saving Tip: For the holidays, I usually put it together ahead of time and then bake it fresh just before serving. It makes life so much easier.
Scalloped Potatoes vs Potatoes au Gratin
So what is the difference between scalloped potatoes and au gratin potatoes? They’re both very similar, containing potatoes (and often onions) baked in a creamy sauce. Au Gratin is defined as covered with breadcrumbs or cheese, scalloped refers to “bake with milk or a sauce”.
In the case of this recipe, the difference is the cheese. That being said, the term scalloped potatoes is still often used if there is cheese within the dish!
Best Potatoes to Use for Potatoes au Gratin
Red-skinned or Yukon Gold potatoes are best for gratin because they hold their shape and don’t need peeling, while starchy russets can turn mushy and are better for mashing.
- Onions: Slice paper-thin so it softens fully and doesn’t stay crunchy.
- Mustard Powder: A small amount enhances the cheese flavor (I also add it to my baked mac and cheese!). Swap in a little Dijon stirred off the heat.
- Cheese: For the best potatoes au gratin, use bold, sharp cheeses like Gruyère or cheddar, with provolone or Swiss as good substitutes.
- Variations: Add flavor with minced garlic, garlic powder, or fresh herbs like thyme or rosemary. You could also include ham or cooked bacon for a heartier casserole.
How to Make Potatoes Au Gratin
- Prep: Thinly slice the potatoes and onions (full recipe below).
- Assemble: Stack the potato slices and onions in the casserole dish.
- Sauce: Cook the cheese sauce in a saucepan, then pour it over the potato and onion slices.
- Bake: Bake until the potatoes are tender and the sauce is bubbly.
PRO TIP: For a quicker version, layer potatoes and onions, cover, and microwave 10 minutes. Add cheese sauce and bake 45–55 minutes as directed. Just as delicious, but a little quicker!
Make-Ahead, Storing, and Reheating
Make up to 24 hours ahead. Keep potatoes covered in sauce, cover tightly, and refrigerate. Bring to room temperature before baking, and add 10–20 minutes to the bake time.
Leftover potatoes au gratin will keep in the refrigerator for up to 4 days. Let it cool completely, then cover tightly with plastic wrap, or transfer to an airtight container before refrigerating.
To freeze, allow it to cool completely and wrap the dish well with both plastic wrap and aluminum foil, or portion it into freezer-safe containers. It will keep for up to 2 months in the freezer.
For best results, thaw overnight in the refrigerator before reheating. Reheat covered in the oven at 350°F until hot throughout (about 20 to 30 minutes), removing the cover near the end to crisp up the top again. Avoid microwaving frozen potatoes, as it can make the sauce grainy and the potatoes watery.
More Holiday Side Dishes
Did you make this Potatoes au Gratin recipe? Leave us a rating and comment below.
Ingredients
- 2½ pounds red potatoes
- 1 medium 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 thinly 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.
- In a saucepan, melt butter and flour and cook for 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 the stacks to allow the sauce to seep between the layers. Cover with foil (sprayed with cooking spray) and bake for 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
- Slice potatoes as thinly as possible.
- Shred your own cheese from a block for the best results. Fresh herbs (such as thyme or rosemary) and garlic can be added to the sauce if desired.
- To reduce baking time, wrap a microwave-safe casserole dish in plastic wrap before adding the cheese sauce and microwave on full power for about 10 minutes (be careful, it will be hot when removing the plastic wrap). Add the cheese sauce and bake as directed for about 45-55 minutes.
- Additional cheese (cheddar or parmesan) can be sprinkled on top once the foil is removed if desired.
- Store leftovers in an airtight container for up to 4 days. Reheat in the oven or the microwave.
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.
Two thumbs up!
I made these for Easter and I’m making them tonight. At Easter i followed the recipe exactly. Everyone loved them. Tonight, since my chicken is marinating with a cumin/chili mixture, I added some cayenne powder to the cheese sauce for a little zip! It’s baking now and I’m sure will be delicious in about an hour!
Sounds like a great addition Leigh Anne! Enjoy!
I made this recipe, and i only had 2 cups of cheddar cheese. The mild curdled, but i didnt think i had enogh potatoes. I like my potatoes more on the ‘spicier’ side. So I added more garlic powder, onion powder, paprika on the top, and yes a little bit if nutmeg and more white pepper and black pepper. I did add more cheese later because my sauce was too thin, and we like our au gratin potatoes CHEESY CHEESY!!! I liked the idea of slicing the potatoes and placing them on the side. I actually didn’t slice them all of the way through and they opened up during cooking. I topped with a little paprika on top to pretty them up at then and I also think topping them with chives would be pretty like in the photo. A little ham crumbled up or bacon, would be good too.
We had these for Easter dinner and wow were they delicious! Thank you for your easy, amazing recipes!
I’m so glad you loved them!
Let me know how you like it!
This dish looks delicious. We love potato gratin, and I’m trying to experiment with new recipes because we’re getting bored of the same old taste. The other thing is I’ve been slicing the potatoes a lot thicker. I will definitely try and slice them thinner to see the difference it makes. Oh, and leaving the skin on as well.
It does add some extra flavor Rhonda. Enjoy!
this is in the oven as I type this… Only thing different I did was add some garlic and some crumbled bacon on top! Can’t wait to eat it! Going to go great with the Easter ham!
If I were to double this recipe and put it in a larger pan, say a 9×13, would the cook time be the same?
It may need a little bit of extra time. I’d suggest planning to have it done early as it can sit warm for quite a while.
CAN YOU COOK THESE A DAY AHEAD AND THEN HEAT THEM UP THE NEXT DAY IN THE OVEN? AND AT WHAT TEMP? IM CONCERNED THEY WOULD DRY OUT. THANK YOU, THEY LOOK AMAZING!!!
I haven’t tried cooking this recipe ahead of time. Please let us know how it goes if you try it!
Hi! I am going to make these for Easter dinner! Is it a creamy yellow cheese sauce? That’s what I am looking for, like the old-fashioned yellow cheese creamy potatoes in sauce! Also, can you use russet potatoes vs red potatoes for this? Thank you! Melanie
Russet should work just fine in this recipe. If you use orange cheddar, the cheese will be slightly yellow. Enjoy, Melanie!
Can this be cooked in a crock pot?
I have only tried it as written, but think it would work Laura. You could also try these Cheesy Scalloped Potatoes, a recipe made for the crock pot! Let us know if you try it!
Soooo not what I expected. Sounded so good bit the cheese sauce stayed on top of all the sliced potatoes and onions and was very heavy. Next time I will introduce the cheese sauce a few layers at a time. Nice combo of flavors and textures. Add salt!!!!
I completely agree. This is a cheese sauce on top of potatoes, not a creamy sauce that bathes the potatoes.
Just made this it’s amazing
That’s awesome to hear Monique!
Very good my husband said 5.5 start.
What is that green sprinkle on top. Look very pretty and taste really good.
I add parsley for garnish. :)
Looks like good ! I’ll try this recipe. However, “au gratin potatoes” means nothing. In french, we say “Gratin de pommes de terre”, which could be translated by “Gratin of potatoes” or “Potatoes’ gratin”.
What size dish did you use?
I use a shallow 10″ dish but a 3qt dish should work just fine too.
Planning to make for Christmas. My mother-in-law cannot have onions. Thoughts on how this might turn out without the onions?
I think it would still be delicious!
This is absolutely yummy and a smashing hit every time I make it! The only thing I would change is to use half and half or heavy whipping cream instead of the milk, it definitely enhances the flavor! I also top it with bacon bits and some parsley, it adds flavor…
I am going to have to try it with half and half! I bet it makes it so creamy!!
So easy and so good.
may I know how many servings is this recipe for?
This recipe makes 8 servings.