Potatoes au gratin are an easy cheesy way to make potatoes. Layers of potatoes and onions are baked in a rich cheesy sauce until bubbly.
Holly’s Recipe Highlights For Potatoes Au Gratin
- Flavor: Potatoes au gratin are an easy cheesy version of scalloped potatoes. They’ve got a cheese sauce while scalloped potatoes have a white sauce.
- Skill level: This recipe has a few steps, including slicing the potatoes and making a homemade cheese sauce. It isn’t difficult, but it does take time.
- Recommended tools: To save a lot of time on prep and and make even thin slices, use a mandoline.
- Budget tip: Any variety of cheese can be used; ensure you’re using a bold flavored cheese.
- Time-Saving Tip: If you’re short on time, check the recipe notes to reduce cooking time.
Ingredient Tips for Potatoes au Gratin
- Choosing 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 best saved for mashed potatoes.
- Onion: Thinly sliced onion adds flavor. For a milder onion flavor, cook it in butter before layering or replace sliced onion with 1 teaspoon of onion powder in the sauce.
- Cheese: Use cheese with a bold flavor in this recipe—I use cheddar and Gruyere and sometimes sprinkle a little Parmesan on top.
- Option: Gruyère cheese can be replaced with provolone or Swiss for a similar flavor.
- Sauce: Made with butter, flour, and milk, this roux-based sauce is finished with shredded 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.
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.
followed recipe to the letter- potatoes were severely under-done (and I know my oven temp is accurate). I sliced yukon golds to 3mm thickness (you can see light through them) with the mandoline. They needed an additional 30 minutes beyond the additional 20 minutes the recipe indicated to brown them. Check your potatoes – pull one from the middle before you serve them to make sure they’re cooked.
Sorry this recipe took longer for you, Matt. I hope you still enjoyed the taste!
Great!
delicious! I added fresh thyme and some garlic for extra flavor. I will be making these again!
Simple recipe to follow and was so delicious! I added fresh thyme and some garlic for extra flavor. I will be making these again!
This tasted very bland. It needed a lot more seasoning. Next time I will season the potatoes, and just add more seasoning overall
Thanks for trying this recipe, Ryan.
Made it and thought there would be leftovers . Nope !! Will definitely be my go to for pot luck dinner next week .
I made this today. I love onions but not in this dish. the dish is very good but I felt like it was missing something. maybe garlic or some bacon.
We recently moved back to my hometown to be near family, and my husband loves this style of potato, so I ran with a new recipe for our inaugural debut spread. I got all excellent reviews from my 79-year young father all the way down to my 5-year old niece. I did a double batch and was a little worried, but baked it in a lasagna pan and baked an extra 10 minutes on the front side, and it turned out great! My husband wants more sauce next time, and that’s an easy fix. It makes a large dish, so I will just shorten the potatoes by a few ounces.
Delicious!
So happy to hear that, KJ! That’s the perfect debut ❤️
I prepared this dish as suggested. We broke the madelin, but luckily I had newly sharpened knives and was able to complete the recipe easily. The red potatoes were really easy to slice. I couldn’t find my round dish, but my rectangular dish worked perfectly. I added about a fourth of a cup of melted butter to the dish just before serving (it didn’t need it!} but my husband loves butter! The dish was beautiful and equally delicious! I promised my son I will make it again!
Thank you Holly!
This recipe, although a little labor intensive, is delicious. My husband really enjoyed them… one of his favorites. I do t typically like potatoes prepared this way, but did really like this recipe. Thank you.
Wow, amazing. The first time I’ve made these and the potatoes are cooked! I used a mandolin, that is the trick. I added 3/4 tsp garlic powder. No salt was added. This is definitely being saved. Next time I will add chopped bacon and jalapenos! Thank you thank you thank you.
These au gratin red potatoes “rocked our world”! I had some medium red potatoes for smashed potatoes, which we always love, but I wanted to try something different. They’re a little extra work, but worth the effort, for sure! Delish! Used my mandolin to slice – a must for easier prep. Thank you for this recipe! I will be using it for Holiday dinners too!
I used pepper cheese & instant potatoes to thicken my cheese sauce. I poured said cheese sauce over pre-cooked (red potatoes) I had leftover in the fridge. Added 1/2 Vadalia onion and 1/2 cup chopped green onions & covered everything in nearly expired sliced American cheese (12 slices). The coup de gras was chopped up deli ham meat over the cheese. 400° for 40 minutes was perfect. Delicious meal !!!
Sounds wonderful Joseph!
the absolute BEST gratin i’ve ever made! we subbed out the gruyère for swiss and it tasted stellar! never had this dish with onions but i will only be making it this way from now on.
Had a dinner party of 10 people and 10 out of 10 loved these potatoes. Need I say more???
This is fabulous!
Easy and I love the fact that it can be made a day ahead.
Varied the cheese to 1 C white sharp cheddar, 1/2 C Gruyere and 1/2 C Colby Jack and added minced garlic to the rue. I will definitely be making this again!
If I wanted to make a truffled version of this could I put a tablespoon or so in the cheese sauce? Wondering if others thought this would go well with the recipe
I haven’t tried it so I can’t say for sure Cheesy, but I think that sounds wonderful! If you try it I would love to hear how it turns out!
It’s spelled roux
This recipe was easy, tasty, and versatile! The cheese can be different, and it can be seasoned in a variety of ways. It is indeed easy and cheesy… :-)
I’m the cook that needs a recipe and hope it turns out, mostly does. I followed this as written and so impressed with this dish, yhe flavors were so good, my husband raved about it.