Potatoes Au Gratin from The Fauxmartha

Sometimes (most times), I’m cooking so fast, I don’t realize what I’m doing—that I just made a roux, which turned into a béchamel, which turned into a proper cheese sauce—until I do something wrong. Then I notice. You know those workouts where they tell you to do the move in slow motion so you can feel every muscle contract? That’s how we’re going to make these Potatoes Au Gratin today, slow enough to feel the roux, the béchamel, and the cheese sauce. 

Potatoes Au Gratin from The Fauxmartha

This post was created in an ongoing partnership with Wolf and the Reclaim the Kitchen initiative. In this two part series, we’ll be zooming in on specific cooking techniques to make the kitchen feel more doable. To bring back the magic. For more kitchen resources, visit ReclaimtheKitchen.com.

How to make a roux from the fauxmartha

The Roux

Let’s start with the start—the roux (pronounced roo). A roux is a mixture of fat (butter) and flour used to thicken a sauce. If you’re not familiar with a roux, you might be familiar with its cousin, the slurry—a mixture of flour (or cornstarch) and a liquid. A roux is a base, used at the start of sauce-making. A slurry is an addition, used midway through or at the end of sauce-making.

Making a roux is as easy as its pronunciation. In a skillet, melt butter. Add equal parts flour (1:1), and whisk together to form an even paste. Cook for an additional 30 seconds to a minute to cook off the raw flour taste. At this point, it’s considered a blonde roux, which is fit for a béchamel or white sauce. Cook it for a couple minutes more, and you’ll have a brown roux, or the start of a brown gravy.

(Note: In the case of this particular recipe, I needed sautéed onions and garlic. So I did that first and built the roux straight into the sauté. It’s flexible like that.)

Potatoes Au Gratin from The Fauxmartha


A béchamel (pronounced bey-sha-mel) is a white sauce made from a roux and milk. It’s the base of cheese sauces, gravies, and gratins, and it’s so simple to make. To the prepared roux, slowly whisk in milk to form a creamy, unbreakable sauce. Slowly is key. (Some say your milk should be extra cold, while others say it should be warmed first before adding into the roux. I’ve never paid a bit of attention to the temperature of my milk, and I don’t think you need to either.) Whisk to evenly combine, cooking over medium heat. In a matter of minutes, the milk will turn into a creamy, smooth sauce. If magic exists, then this is magic.

Potatoes Au Gratin from The Fauxmartha

Cheese Sauce

When you add cheese to a béchamel, you have a smooth, creamy, unbreakable cheese sauce. You know what I mean by unbreakable, right? You know those casseroles where the milk and cheese seem to separate? Well, there’s nothing wrong with that, but a cheese sauce that doesn’t break is just so appetizing. It also makes for a consistent flavor throughout.

Side note: Cheese sauces are far easier to clean out of pans and baking dishes. Have you ever added cheese straight into a sauce without a roux? It’s impossible to get all the cheese off that pot or utensil. This is not the case with a cheese sauce. Magic I tell you.

Potatoes Au Gratin from The Fauxmartha

Sometimes (most times), we’re cooking so fast, we don’t realize what we’re doing, until it goes wrong. Then we notice. I’ve loved partnering with Wolf over these last couple years on their Reclaim the Kitchen initiative. It’s made me reclaim my own. It’s made me sloowwww down and watch melted butter and flour turn into a paste that goes from blonde to brown in a matter of minutes. Oh, that’s how you make a brown gravy, I said to myself the other day. It’s demystified seemingly intimidating French techniques. Come to find out, most of which are quite simple.

Potatoes Au Gratin from The Fauxmartha

Unless you go to culinary school, there’s no manual for cooking. We learn on the job, after work with whatever’s in the fridge. And most days, if you’re anything like me, we’re cooking to be fed or to feed, purely out of necessity. But when, and if, there’s enough time to come up for air, we can slow down and learn to make a proper cheese sauce, if for no other reason than to make cleaning that pot easier. But gosh, that sauce was good. And slowly but surely, we fall back in love with the kitchen. There’s magic in that room.

To learn more basic techniques, tips, and tricks, head over to the Reclaim the Kitchen site, where you’ll find everything from knife skills videos to food safety tips, which I’m reading now. I’m terrified (terrified!) of making someone sick with my food. I love this resource of a site. It’s a lot like my book coming out—a practical guide for making the kitchen more doable. Because that’s really where the magic is.

Potatoes Au Gratin from The Fauxmartha

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Potatoes Au Gratin from The Fauxmartha

Potatoes Au Gratin

  • Prep Time: 30 minutes
  • Cook Time: 1 hour
  • Total Time: 1 hour 30 minutes
  • Yield: 6-8 1x


A simple au gratin with spilled dominos of yukon potatoes, held together by a light and savory cheese sauce, and spotted with thyme. Perfect for the holidays or any chilly winter night.




  • 6 c. thinly sliced yukon gold potatoes (about 2 1/4 lbs.)
  • 1 c. finely diced sweet onion
  • 2 cloves garlic, minced
  • 5 tbsp. unsalted butter, divided
  • 1 tbsp. fresh thyme, plus more for garnish
  • 1/4 c. unbleached all-purpose flour
  • 3 c. whole milk
  • 2 tsp. kosher salt, plus more as needed
  • a couple cracks of pepper
  • 1 1/2 c. grated cheese (mixture of gruyere and cheddar)


  • 2 tbsp. panko
  • 2 tbsp. grated parmesan


Prepare the potatoes. Preheat the oven to 400°F. Using a mandoline, or a sharp knife, thinly slice the potatoes 1/16-thick. Set aside. Finely dice the onion and mince the garlic. Set aside.

In a large skillet over medium heat, melt 1 tablespoon of the butter. Add the onions, thyme, and a pinch of salt, and cook for about 3 minutes, or until translucent. Add the garlic and cook for an additional 30 seconds. Add in remaining 4 tablespoons of butter. Once melted, whisk in flour until completely smooth. Allow to cook for 30 seconds to a minute to toast out the raw flour flavor. This creates a roux.

Slowly pour about 1/4 cup of the the milk into the roux, whisking until smooth. Once smooth, slowly pour in remaining milk, salt, and pepper. Cook for 3-5 minutes until a creamy sauce forms, whisking continually. This creates a béchamel.

Slowly sprinkle in the cheese, whisking after each addition until smooth. Cook a minute more. This creates an unbreakable cheese sauce. Remove from heat. Taste, adding more salt if necessary. Note: This sauce will be on the salty side to carry the weight for the potatoes.

In a 9″ x 11.5″ enamelware pan (or something similar), add enough sauce to coat the bottom of the pan. Begin adding potatoes like spilled dominos, overlapping about 1-inch (see image above), until you have a solid layer of potatoes. Liberally cover with sauce, then add potatoes. Repeat until all potatoes are used, ending with a layer of sauce. Tightly cover with foil and bake for 30 minutes.

Prepare the gratin. After 30 minutes, remove from oven. Discard foil and top with the gratin. Bake for 20-30 minutes more. Sprinkle with additional thyme and serve warm.


The cheese sauce can be made ahead of time and stored covered in the fridge. Reheat for a couple minutes to make spreadable again.

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Post Sources

Copper Pots | Ceramic Bowl | Enamel Baking Dish | Olive Wood Spoon

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