With thinly sliced potatoes, onions, and two types of cheese, these simple Au Gratin Potatoes make an excellent side to your holiday ham or turkey, or even your everyday pork chops or steak. They can even be prepared in advance.
Easy & Cheesy Au Gratin Potatoes
This au gratin potatoes recipe is one of those side dishes that sounds a bit fancy, like something you’d order at a restaurant, but is actually simple to make. All you need is potatoes, onions, cheese, and a few pantry staples. It’s amazing how a few basic ingredients can result in such an impressive dish.
We love to serve this as a holiday side dish but it is simple enough to make for a regular weeknight dinner too. Not to mention the fact it can be assembled in advance, which is perfect for those busy evenings.
Why You’ll Love This Au Gratin Potatoes Recipe
- Only a handful of ingredients. You’ll need potatoes, cheese, onion, and just a few pantry staples to bring this au gratin potatoes recipe together.
- Super cheesy. The best part of this casserole is definitely the cheese – a combination of shredded cheddar and Gruyere is used for depth in taste and flavor.
- Easy to prep in advance. One of my favorite things about this recipe is that I can easily prep it a day in advance, then just pop it in the oven and enjoy. Perfect for the holidays!
Au Gratin Potatoes vs Scalloped Potatoes
What’s the difference between au gratin potatoes and scalloped potatoes? Truthfully, both dishes are very similar and, at this point, the terms are often used interchangeably.
Both dishes are made with sliced potatoes and onions in a cheese sauce, though au gratin potatoes are sometimes considered “fancier” and are typically topped with breadcrumbs or more cheese.
My scalloped potatoes recipe includes a few herbs and seasonings that you won’t find in this recipe and I use different types of cheese in both recipes as well.
You’ll need just a handful of ingredients for this recipe.
(Be sure to check the recipe card below for details and measurements.)
- Potatoes – Russet potatoes are the best option for au gratin potatoes.
- Onion – Thinly sliced onion adds extra flavor to this dish.
- Butter – Helps create a rich, savory sauce.
- Flour – Thickens the sauce.
- Whole milk – This can be made with a milk substitute to your taste, like almond milk, but the sauce won’t be as rich and creamy.
- Cheese – I use cheddar cheese in the casserole and Gruyère on top. For best results, use freshly shredded cheese and avoid pre-packaged for the recipe.
- Seasonings – Garlic powder, salt, and pepper are the only seasonings you’ll need.
- Garnish – Fresh chopped parsley or chives finish the dish with a bit of added taste and color.
How to Make Au Gratin Potatoes
This recipe requires just 20 minutes or so of prep.
(Be sure to check the recipe card below for more detailed instructions.)
- Layer the potatoes and onions. Slice the potatoes to no more than 1/8-inch thick. Layer half in the casserole pan, top with onions, and finish with the remaining potatoes.
- Make the sauce. Melt the butter then stir in the flour and cook for 2 minutes. Slowly whisk in the milk until well combined then add the cheddar cheese and seasonings. Pour over the potatoes.
- Bake. Cover the pan with foil and bake at 375F for 45 minutes.
- Add the cheese. Uncover the pan and top with the Gruyere cheese. Bake for another 35 to 45 minutes until golden brown and bubbling.
- Enjoy. Let rest for 15 minutes, garnish with fresh chopped parsley or chives, then slice and serve!
Tips for Success
- Use a mandolin to slice the potatoes. For more even slices and cooking, I highly recommend slicing the potatoes using a mandolin.
- Swap out the Gruyère. You can change the Gruyère for white cheddar or use more yellow cheddar, if preferred.
- Add some ham. Feel free to add in some diced cooked ham. Bacon crumbles would also work.
- Shred your own cheese. For the best flavor and texture, shred your cheese from the block if possible.
- Cool before serving. Letting the casserole rest for 15 minutes before serving gives the cheese sauce a chance to thicken a bit and makes it much easier to slice and serve.
Au gratin potatoes make a wonderful holiday side dish next to spiral ham and roasted turkey. They’re also easy enough to whip up for any weeknight dinner and pair just as well with steak, pork chops, and baked chicken breast.
Make-Ahead and Leftover Storage
- Can I Make Au Gratin Potatoes in Advance? Absolutely. I like to assemble the pan of au gratin potatoes and then store it in the refrigerator until I want to cook it. Ensure you allow it to warm up on the counter for 15-20 minutes before you try to bake it off.
- Storing leftovers. Any leftover au gratin potatoes should be stored in an airtight container in the refrigerator for up to 4 days.
- Reheat. You can reheat the pan, covered, in the oven or individual servings in the microwave.
More Potato Side Dishes:
Au Gratin Potatoes
- 6 medium russet potatoes , peeled
- 1 small onion , sliced thin
- 1/4 cup butter
- 1/4 cup all-purpose flour
- 1 & 1/2 cups whole milk
- 2 cups freshly shredded cheddar cheese
- 1 teaspoon garlic powder
- 1 teaspoon salt
- 1 teaspoon pepper
- 1/2 cup shredded Gruyère cheese
- fresh chopped chives or parsley , for garnish
- Preheat your oven to 375°F. Spray a 2-quart casserole pan with nonstick spray.
- Thinly slice the potatoes to no more than 1/8 inch thick.
- Arrange half the potatoes in the casserole pan and top with the onions. Top the onions with the remaining potatoes.
- In a medium saucepan, melt the butter. Slowly stir in the flour and cook for 2 minutes until no white streaks remain, stirring the entire time. Slowly whisk in the milk until well combined. Mix in the cheddar cheese, garlic powder, salt, and pepper until the cheese has melted.
- Pour the cheese sauce over the potatoes.
- Cover the pan tightly with aluminum foil and bake for 45 minutes.
- Uncover the casserole dish and sprinkle the Gruyere cheese over the top. Bake for an additional 35-45 minutes until it is golden brown and bubbling.
- Let rest 15 minutes, garnish with fresh chopped parsley or chives, then slice and serve.