The Best Potatoes au Gratin Ever

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creamy potatoes au gratin recipe
Photo: Liz Andrew/Styling: Erin McDowell

Fact: Mashed doesn’t have to be your default when it comes to potato side dishes. Because potatoes just got a serious upgrade. Take this recipe for potatoes au gratin. You know, the version where slices of spuds are smothered in a cream sauce and plenty of cheese? It’s rich and comforting—plus, it can be assembled ahead of time and held in your refrigerator until you’re ready to bake it. 

We like serving this decadent gratin next to pork tenderloin and a crunchy slaw but it can just as easily be the star of the show with a simple side salad. And although we’ve opted for nutty Gruyère to balance out the creaminess of this classic French dish, you can—and should—experiment with different cheeses (cheddar would work well). So...our place or yours?


5 tablespoons unsalted butter, divided

1 sweet onion, thinly sliced

3 garlic cloves, minced

1 tablespoon grainy mustard

2 cups half-and-half

2 pounds potatoes, peeled and thinly sliced

Salt and freshly ground black pepper

½ teaspoon freshly grated nutmeg

¾ cup grated Gruyère cheese


1. Preheat the oven to 375°F. Grease a 9-by-13-inch casserole dish with 1 tablespoon of the butter.

2. In a large pot, heat the remaining 4 tablespoons of butter over medium heat. Add in the onion and sauté until tender and translucent, about 4 to 5 minutes. Add the garlic and cook until fragrant, 1 minute more.

3. Stir in the mustard. Then add the half-and-half and bring to a simmer. Add the potatoes and simmer for 4 to 5 minutes. Season with the salt, pepper and nutmeg.

4. Pour the potato mixture into the prepared casserole dish and spread into an even layer. Top with the cheese in an even layer. (The dish can be stored, covered, in the refrigerator at this point if you want to prepare it ahead.)

5. Bake until the cheese is golden, the sauce is bubbly and the potatoes are easily pierced with a fork, 25 to 30 minutes (add 5 to 7 minutes if baking after storing in the refrigerator). Let cool 5 minutes before serving warm. Prepare thy tastebuds. 

Nutrition Facts
  • 299 calories

  • 18g fat

  • 27g carbs

  • 8g protein

  • 6g sugars

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Note: The information shown is Edamam's estimate based on available ingredients and preparation. It should not be considered a substitute for a professional nutritionist's advice.

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