Cheesy Au Gratin Potatoes

Thin slices of tender potatoes held together with a creamy cheese sauce and seasonings. This au gratin potatoes might be the ultimate in potatoes side dish recipes… next to cheesy twice baked potatoes, of course. Worthy of a special occasion, being a whole meal or for potlucks.

 

This easy potatoes au gratin recipe has so many variations that you will literally never make the same batch twice. Sometimes referred to as Dauphinoise, these are the ultimate of potato sides for any holiday table.

Why You’ll Love These Potatoes

Cheesy potatoes thinly sliced and baked in a bubbly, decadent sauce- what’s not to love!

• Great side dish – This super versatile potato side dish can be served with just about anything you can think of! The perfect complement to holiday or weeknight dinners.
• Rich and creamy – If you’re looking for comfort food, you’ve got it with these easy au gratin potatoes!
• Easy to make – You can have these creamy au gratin potatoes ready and on the table with only 20 minutes of prep time!

Au Gratin Potatoes vs Scalloped Potatoes

First, let’s discuss one of the most common mistakes made in cooking next to aioli: what is the difference between au gratin potatoes and scalloped potatoes? The main difference really is easy: CHEESE.

Foodie friends, au gratin potatoes and scalloped potatoes are not the same thing. Cheesy, rich and totally decadent, homemade au gratin potatoes are always welcome on my table. While they are most revered as a side dish, I could eat them as my entrée and be perfectly content.

Scalloped potatoes are baked in a cream sauce, basically a seasoned roux, while au gratin potatoes are made with a cheese sauce- the roux with cheese.

I love both, but if I have the choice to add cheese, why in the world wouldn’t I?

Roux

I am going out on a limb here and saying that nearly all cheese sauces start with a roux, which is combination of fat and thickener, in most cases butter and flour, then thinned with milk.

This mother sauce is the base for everything from jambalaya to cheese sauce that will grace broccoli, mac and cheese, dipping sauces and of course, au gratin potatoes.

The beauty of a nice roux is that it is a blank slate waiting for the cheese to give it personality and flavor. While for this recipe we choose a classic cheddar cheese, this is one of the many ways you can customize, by swapping a different cheese. Even use a blend, cleaning out the cheese drawer.

What Potatoes are Best for Au Gratin Potatoes?

Another simple easy answer- starchy ones like russet potatoes or yukon gold potatoes. They have a low moisture content so excess liquid won’t thin out the cheese sauce, and a raw gritty flesh that gets creamy when cooked.

The starch not only helps to thicken the cheese sauce and bind it all together, they can withstand long cooking times. Since this potato casserole is essentially a brick of potato, it needs 1 hour or more to be fork tender.

The most common starchy potatoes are Yukon Gold, Russets or Idaho potatoes. The downside is that these varieties also have thick and hard to chew skins, so you will have to peel them before using. Waxy potatoes like red potatoes can cook to be mealy or mushy.

Cutting the Potatoes

While you can go the good, old fashioned route and try your hand at uniform slices with a handheld knife, you can can also use a food processor or mandoline slicer.

Having your potatoes slices be as close to the same thickness as possible will help them cook evenly. These tools also just make the process fast.

Au Gratin Potatoes Ingredients

Only a few ingredients are needed to make this creamy sauce with potatoes.

• Potatoes– Read above, starchy potatoes, about 4-5.
• Unsalted butter- if using salted, omit salt below.
• Flour– all-purpose flour works best, but flour alternatives can be used as long as they have thickening properties. ‘
• Whole Milk- dishes like this aren’t really supposed to be “skinny” and therefore I don’t skimp on the milk. Full fat for me! It will work with a lower fat content, but it may not be as thick with less fat. You can also use a combination of lower fat milk with heavy cream, just not all cream.
• Seasonings– coarse Kosher salt, bay leaf, garlic powder, onion powder and white pepper. Any of these are optional and can be increased depending on your taste. Black pepper can also be used, but I like white because it is a tad milder and won’t have little black flecks.
• Cheese- See above under the section on roux, we used sharp cheddar cheese for these au gratin potatoes, but nearly any harder cheese that melts well can be substituted. Swiss, white cheddar, pepper jack, Monterey jack, gouda, gruyere cheese are my others favorites.

How to Make Au Gratin Potatoes

This dish is a little more time consuming than most of our recipes, but it is totally worth it.

1. Make roux. In a small saucepan over medium heat, melt the butter and whisk with flour until a paste forms. While whisking, add the milk. Add the seasonings and reduce to low heat with a gentle simmer. This achieves several goals: scalds the milk so the sauce is thicker, heats so that the cheese can melt in smoothly, infuses the sauces with flavor from the bay leaf and other seasonings and thickens.
2. Add cheese. After the milk mixture comes to a low simmer, whisk in the shredded cheese until smooth. Turn off the heat and allow to cool slightly before using. Isn’t it amazing that you actually don’t need that much cheese to make a cheesy sauce?
3. Soak potatoes. Meanwhile, start to prep the potatoes. Fill a large mixing bowl with cold water and a little bit of salt. Placing the potato slices in this mixture will prevent them from browning. Browning doesn’t impact the flavor, but is unsightly.
4. Cut potatoes. Peel the potatoes using a Y peeler, then cut to 1/4 or less thickness using your desired cutting method as described above.
5. Layer potatoes and sauce. Grease a baking dish and then place half of the sliced potatoes in the bottom, topping half of the cheese sauce. Top with the remainder of the potatoes and then cheese sauce. Cover with aluminum foil and bake.
6. Top with cheese. Remove from the oven and take the cover off, sprinkle with the remaining cheese. Return to the oven for cheese to melt.
7. Let rest. Now is the hardest part… allow the au gratin potatoes to sit. Much like meat, they need to rest in order for the sauce and liquids to reabsorb into the dish. Slicing immediately will most certainly result in them being delicious, but not suitable for a plate, more like a bowl situation.

Au Gratin Potatoes Variations

You’ll never make the same batch twice!

• Add bacon- because bacon makes everything better. Mix about 1/2 cup of crumbled bacon into the cheese sauce when it is complete and you’ll have potatoes au gratin with bacon!
• Real onion– Saute some leeks or white onion and fold it into the cheese sauce. Also top with scallions or chives.
• Roasted garlic cloves– the smoky flavors from roasted garlic can’t be beat. Roast and smash a whole head and add it to the cheese sauce.
• Heat- add a little spice by adding chopped jalapenos to the cheese sauce and swapping the cheese for pepper jack.
• Smoky– Smoked paprika and smoked cheeses will give this recipe a hint of flavor unusual for potatoes.
• Crunchies– I am a sucker for a crunchy topping! After the potatoes and cheese has baked, feel free to add bread crumbs, crumbled crackers, croutons or even Goldfish crackers to the top of the potatoes.

Make Ahead, Storage & Freezing

Can You Make Au Gratin Potatoes Ahead of Time?

The good news is that even though these au gratin potatoes take a little time and elbow grease to make, they are also make ahead friendly. My husband might even tell you that leftovers the next day are even more delicious than the fresh potato casserole. He likes to eat them cold or at room temperature. Make up to one day ahead of time.

How do You Store Au Gratin Potatoes?

Store covered and in the refrigerator for up to 5 days in an airtight container or with the casserole dish covered in plastic wrap. Leftovers can be reheated in the oven or the microwave, but be mindful that high temps in the microwave can make the cheese sauce separate and look oily.

Can you Freeze Au Gratin Potatoes?

To freeze, follow our instructions for how to freeze a casserole. To cook, cook from frozen at 350°F, covered for up to one hour or until the center is hot. It might require a fresh topping of shredded cheese to freshen it up.

Frequently Asked Questions

More Potato Dishes

• Potato Pie
• Truffle Fries
• Sweet Potato Casserole