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Potatoes Au Gratin are a classic potato dish that is easy to make at home and is sure to win over any crowd. Thinly sliced potatoes combine with a rich béchamel sauce to give you the best side dish.

Wooden spoon serving portion of Potatoes Au Gratin from baking dish of Potatoes Au Gratin. - 3

This au gratin potatoes recipe went through multiple rounds of testing until I had the perfect recipe. The potatoes in this are perfectly tender, the sauce is creamy and rich, and this dish is packed with the best flavor. You will love this creamy potato side dish.

Scalloped Potatoes vs Au Gratin

Potatoes au gratin are made with thinly sliced potatoes baked in a creamy sauce that includes layers of melted cheese, giving the dish its rich, golden, and slightly crispy top. Scalloped potatoes are traditionally baked in a cream or milk-based sauce. Both are delicious comfort food classics!

Overhead view of ingredients for Potatoes Au Gratin recipe on countertop. - 4

Ingredients

Scroll to the recipe card at the bottom of the post for the full list of ingredients and their measurements needed for these homemade au gratin potatoes.

  • Potatoes: The base of this potatoes au gratin recipe, be sure to slice the russet potatoes very thin, about 1/8 inch (3 mm) thick so they cook evenly and layer nicely. This is best to do with a mandoline slicer . I prefer to peel my potatoes, but you can keep the peels on if you prefer.
  • Onion and garlic: Sautéd in butter to add a great savory flavor to the sauce.
  • Butter: Forms the base of the creamy roux that will become the sauce.
  • Flour: Thickens the sauce and prevents it from separating.
  • Half and half: Gives the sauce the perfect creamy texture and consistency.
  • Cheese: Freshly grated cheddar cheese from a block will melt and taste so much better than pre-shredded cheese. I do not recommend using a sharp cheddar for this recipe as it will separate too much during baking.

How to Make Au Gratin Potatoes

Here is a brief overview of how this au gratin potatoes recipe comes together. For the full recipe, including all ingredients and their measurements, scroll to the recipe card at the bottom of the post.

Sauté the Onion and Garlic

Melt butter in a skillet and cook the onion and garlic until soft.

Overhead view of a pot of ingredients for Potatoes Au Gratin recipe - 5

Whisk in the Flour

Whisk in the flour until you no longer see any streaks of white. Then slowly whisk in the half and half, a few tablespoons at a time, adding more only once what you have just added has been absorbed. While you want to go slowly, this should only take about one minute. Bring to a simmer.

Overhead view of a pot of ingredients and flour for Potatoes Au Gratin recipe - 6

Stir in the Cheese

Whisk in a few handfuls of cheddar cheese at a time, adding more cheese once what you have just added is melted.

Overhead view of a pot of ingredients for Potatoes Au Gratin recipe with whisk for stirring. - 7

Layer the Potatoes

Layer half the potatoes in the bottom of the prepared pan. Top with half of the prepared cheesy cream sauce. Layer the second half of the potatoes. Top with the remaining creamy cheese sauce.

Overhead view of a baking dish of Potatoes Au Gratin recipe with sliced potatoes - 8

Bake the Potatoes

Add the remaining cheese to the top. Cover the casserole dish with foil and bake in a preheated oven for 70 minutes. Remove the foil and continue baking for 20 minutes.

Overhead view of a baking dish of Potatoes Au Gratin recipe before baking - 9

Storing and Reheating Leftovers

Store any leftover au gratin potatoes in an airtight container in the refrigerator for up to three days. Reheat only the portion you plan to eat in the microwave on half power or in the oven at 350 degrees Fahrenheit until heated through.

Baking dish of Potatoes Au Gratin with portion taken out. - 10

What to Pair with Potatoes Au Gratin

  • Baked Salmon
  • Roast Turkey Breast
  • Shaved Brussel Sprout Salad
  • Roasted Root Vegetables

If you make this potatoes au gratin recipe or any of my other recipes, I’d love to hear what you think!

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Ingredients

  • 3 tablespoons unsalted butter
  • 1 small yellow onion diced
  • 3 garlic cloves minced
  • 1 teaspoon kosher salt or 1/2 teaspoon table salt
  • 1/8 teaspoon black pepper
  • 3 tablespoons all purpose flour
  • 2 cups half and half
  • 2 cups cheddar cheese shredded, divided, see note 1
  • 3 medium russet potatoes about 2 pounds, sliced thin, see note 2
  • 1/4 cup Parmesan cheese

Instructions

  • Preheat your oven to 350 degrees Fahrenheit. Spray a 2-quart casserole dish with cooking spray.
  • In a small saucepan over medium heat, melt the butter. Add in the onions, garlic, salt, and pepper. Sauté until the onions start to soften, about three minutes. 3 tablespoons unsalted butter, 1 small yellow onion, 1 teaspoon kosher salt, 1/8 teaspoon black pepper, 3 garlic cloves
  • Whisk in the flour until you no longer see any streaks of white. Then slowly whisk in the half and half, a few tablespoons at a time, adding more only once what you have just added has been absorbed. While you want to go slowly, this should only take about 1 minute. Bring to a simmer. 3 tablespoons all purpose flour, 2 cups half and half
  • Add 1 1/2 cups of the cheddar cheese, a few handfuls at a time, whisking to combine. Add more cheese once what you have just added is melted. 2 cups cheddar cheese
  • Layer half the potatoes in the bottom of the prepared pan. Top with half of the prepared cream sauce. Layer the second half of the potatoes. Top with the remaining cream sauce, then add the remaining 1/2 cup cheddar cheese and the Parmesan cheese. 2 cups cheddar cheese, 3 medium russet potatoes, 1/4 cup Parmesan cheese
  • Cover the casserole dish with foil and bake for 70 minutes. Remove the foil and continue baking for 20 minutes.

Notes

  1. Do not use sharp cheddar as it is more likely to separate while baking.
  2. The russet potatoes should be sliced to 1/8 inch (3 mm) thickness. This is best done with a mandoline slicer .
Baking dish of Potatoes Au Gratin with portion taken out. - 11

did you make this

Au Gratin Potatoes

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Baking dish of Potatoes Au Gratin with portion taken out. - 12

Au Gratin Potatoes

Ingredients

  • 3 tablespoons unsalted butter
  • 1 small yellow onion diced
  • 3 garlic cloves minced
  • 1 teaspoon kosher salt or 1/2 teaspoon table salt
  • 1/8 teaspoon black pepper
  • 3 tablespoons all purpose flour
  • 2 cups half and half
  • 2 cups cheddar cheese shredded, divided, see note 1
  • 3 medium russet potatoes about 2 pounds, sliced thin, see note 2
  • 1/4 cup Parmesan cheese

Instructions

  • Preheat your oven to 350 degrees Fahrenheit. Spray a 2-quart casserole dish with cooking spray.
  • In a small saucepan over medium heat, melt the butter. Add in the onions, garlic, salt, and pepper. Sauté until the onions start to soften, about three minutes. 3 tablespoons unsalted butter, 1 small yellow onion, 1 teaspoon kosher salt, 1/8 teaspoon black pepper, 3 garlic cloves
  • Whisk in the flour until you no longer see any streaks of white. Then slowly whisk in the half and half, a few tablespoons at a time, adding more only once what you have just added has been absorbed. While you want to go slowly, this should only take about 1 minute. Bring to a simmer. 3 tablespoons all purpose flour, 2 cups half and half
  • Add 1 1/2 cups of the cheddar cheese, a few handfuls at a time, whisking to combine. Add more cheese once what you have just added is melted. 2 cups cheddar cheese
  • Layer half the potatoes in the bottom of the prepared pan. Top with half of the prepared cream sauce. Layer the second half of the potatoes. Top with the remaining cream sauce, then add the remaining 1/2 cup cheddar cheese and the Parmesan cheese. 2 cups cheddar cheese, 3 medium russet potatoes, 1/4 cup Parmesan cheese
  • Cover the casserole dish with foil and bake for 70 minutes. Remove the foil and continue baking for 20 minutes.

Notes

  1. Do not use sharp cheddar as it is more likely to separate while baking.
  2. The russet potatoes should be sliced to 1/8 inch (3 mm) thickness. This is best done with a mandoline slicer .

Nutrition

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