The humble potato gets dressed up with just a few simple ingredients in this Potatoes au Gratin Gruyère. The process is simple (much simpler than most recipes) and the result is a potato au gratin that is flavorful and cheesy without being overly heavy. It’s perfect for the holidays!
Why You’ll Love This Recipe
There are a lot of reasons to love this Gruyère Potatoes au Gratin! It’s creamy and flavorful but not too heavy like so many au gratins can be. The fast and the short of it:
- Easy to make
- No stove-top cooking required
- Elegant and elevated
- Not too heavy
Ingredients You’ll Need
- Olive oil: a good extra-virgin olive oil is preferred here.
- Sage: we tested this recipe with thyme but found fresh sage just worked better. The fried sage on top is really the cowbell. Use any leftover sage in our Hasselback Sweet Potatoes.
- Gruyère cheese: we developed this recipe using Gruyère cheese. It’s nutty, savory and a tad funky. You can substitute with Parmesan, manchego and/or aged white Cheddar. Leftover Gruyère can be used in our Cauliflower Gratin.
- Yukon gold potatoes: the best potatoes for au gratin are yukon gold (red skinned potatoes are also great). Unlike russets, they’re tender and creamy. Yukon gold potatoes make great cheesy mashed potatoes and sour cream potato salad.
- Flour: I like to make this recipe with whole-wheat flour, but you can also use all-purpose flour. You only need ¼ cup.
- Garlic: we recommend making this with fresh garlic, though garlic powder can be used instead.
- Nutmeg: freshly grated is preferred (it has more flavor). I recommend storing whole nutmegs in the freezer for longer storage.
- Kosher salt and ground black pepper: we develop all of our recipes here with Morton kosher salt. If you’re using Diamond Crystal, increase the amount of salt by at least half.
- Half-and-half: the perfect middle ground—creamy but not too heavy. You can also use a combination of equal parts whole milk and heavy cream.
How to Make Potatoes au Gratin with Gruyère Cheese
- Fry the Sage
- Slice the Potatoes
- Toss the Potatoes with Flour
- Layer the Gratin
- Bake & Serve
Heat the olive oil in a cast-iron skillet until shimmering. Add the sage and fry until crispy, fragrant and just starting to brown.
Transfer the sage leaves to a paper-towel-lined plate using cooking tweezers or a slotted spoon. Pour the excess oil into a heat-proof bowl, but don’t scrape it clean. You want to retain a thin layer of oil on the pan so the potatoes don’t stick.
Slice the potatoes very thinly (about ⅛-inch thick). A mandoline is the best way to do this, but if you’ve got a very sharp knife and impressive knife skills, you can do it by hand.
When you’re ready to layer, toss the potatoes with the flour, minced garlic and nutmeg. Add the salt and pepper and toss to combine.
Layer ⅓ of the potatoes in the bottom of the cast-iron skillet, this will be about 3 layers of potatoes. Sprinkle cheese over top. Repeat layering of potatoes and cheese three more times.
Pour the half-and-half over the potatoes then drizzle with the sage-infused oil.
Tightly cover the pan with foil and bake for 30 minutes. Remove the foil, increase the oven temp and bake until the gratin is reply golden brown, this will take about 25 minutes.
Expert Tips From the Test Kitchen
Expert Tips From the Test Kitchen
- Layer the gratin quickly after tossing the potatoes with salt. Letting the potatoes sit too long after seasoning can cause the mixture to become too wet and soggy (salt draws out moisture).
- Use a 9-inch cast-iron skillet. Anything larger will make for a very thin au gratin.
- Keep an eye on the sage—it can go from perfectly fried and crispy to burnt.
- For the best potatoes au gratin, use block cheese and shred it yourself. It melts smoother than pre-shredded will.
Potatoes au Gratin vs Scalloped Potatoes
The two terms are often used interchangeably, though they do translate differently. Au Gratin is translated as covered with breadcrumbs or cheese, scalloped translated to “bake with milk or a sauce.”
The way we like to think of it, potatoes au gratin tend to be cheesier and a bit more focused on potato. Scalloped potatoes usually have a creamy cheese sauce, not just shredded cheese.
Make Ahead & Storage Information
We don’t recommend assembly the gratin ahead of time, though you can prep components ahead of time.
- Shred the cheese and slice the potatoes, place the potatoes in a bowl of water and refrigerate for up to 3 days.
- Fry the sage and keep the fried sage at room temperature for up to 1 day.
- When ready to bake, drain the potatoes and pat them dry before tossing with the flour, garlic, nutmeg, salt and pepper.
Storage: leftovers can be stored in an airtight container in the refrigerator for up to 5 days.
If flour was not added to the potatoes prior to baking the gratin will be watery. Flour works as a thickener and soaks up the water. Secondly, if the potatoes were seasoned with salt and left to sit for 15 to 30 minutes prior to layering and baking, this could be the problem. Salt draws out moisture, so be sure to layer and bake the gratin immediately after seasoning the sliced potatoes.
Absolutely, use equal parts whole milk and heavy cream instead of half-and-half.
Aged white cheddar, Parmesan, Manchego and aged gouda are all great substitutes. You can also use a mixture of any of these.
We haven’t tested this, but I worry the salt will draw out excess moisture from the potatoes and make them watery. If you try it, let us know how it goes!
Alternatively, if you want to get ahead on the prep work, you can shred the cheese and slice the potatoes. Place the potatoes in a bowl of water and refrigerate. Fry the sage and keep them at room temperature. When ready to bake, drain the potatoes and pat them dry before tossing with the flour, garlic, nutmeg, salt and pepper.
Nope, you do not need to peel the potatoes for au gratin.
Gruyère Potatoes au Gratin
- 2 tablespoons olive oil
- ¼ cup packed fresh sage leaves
- 8 ounces Gruyère cheese
- 2 pounds yukon gold potatoes scrubbed clean
- ¼ cup whole-wheat flour or all-purpose flour
- 3 cloves garlic, minced, or ½ teaspoon garlic powder
- ¼ teaspoon freshly grated nutmeg
- Kosher salt and freshly ground black pepper
- ¾ cup half-and-half
- Preheat oven to 375ºF with rack set in middle position.
- Heat 2 tablespoons olive oil in a 9-inch cast iron skillet over medium-high until shimmering. Add ¼ cup packed sage leaves and fry until crisp and starting to brown, 3–5 minutes. Using a slotted spoon or cooking tweezers, transfer leaves to a paper-towel-lined plate. Pour excess oil into a heat proof bowl (do not scrape the pan clean thought); set oil aside.
- Using a large-hole grater, shred 8 ounces Gruyère cheese; set aside.
- Using a mandoline, thinly slice 2 pounds potatoes to ⅛-inch thick; transfer to a large mixing bowl. Add ¼ cup flour, 3 minced garlic cloves, and ¼ teaspoon nutmeg to potatoes; toss to combine. Add 1 teaspoon kosher salt and 1 teaspoon black pepper; toss to combine.*
- Layer ⅓ of potatoes in cast-iron skillet (this will be about 3 layers of potatoes). Sprinkle ⅓ of cheese over potatoes. Layer another ⅓ of potatoes followed by another ⅓ of cheese. Repeat layering once more with reminiang potatoes and cheese.
- Pour ¾ cup half-and-half over potatoes, distributing evenly. Drizzle reserved sage oil over top. Tightly cover skillet with foil and bake 30 minutes. Remove foil, increase oven temperature to 400ºF and bake until deply golden brown, 25–30 minutes. Crush fried sage over top and serve.