These creamy au gratin potatoes are a comforting, classic side dish made with thinly sliced Yukon Gold potatoes and diced onion baked in a rich, cheesy béchamel until tender and golden brown.
They pair beautifully with holiday mains or special meals and are a close cousin to traditional scalloped potatoes.
Potatoes au gratin — however you pronounce it — delivers tender, creamy layers of potato in a savory cheese sauce with those irresistible golden, crispy edges. While often served as a side, they can steal the show whenever they’re on the table.
Table of contents
- Ingredients for Au Gratin Potatoes
- Best Potatoes for Au Gratin Potatoes
- Do You Peel Potatoes for Au Gratin Potatoes?
- How to Make Creamy Au Gratin Potatoes
- How to Thinly Slice Potatoes
- Make the Cheese Sauce
- Assemble the Au Gratin Potatoes
- Variations
- Make-Ahead Au Gratin Potatoes
- How to Reheat Au Gratin Potatoes
These potatoes complement ham, roast turkey, or beef tenderloin and work well for Easter, Thanksgiving, Christmas, or any special meal where a rich, comforting side is welcome.
Ingredients for Au Gratin Potatoes
- Potatoes – Yukon Gold potatoes are recommended for their creamy texture and flavor.
- Seasoned salt – A mild all-purpose seasoned salt brightens the dish.
- Onion – Diced sweet yellow onion adds sweetness and depth.
- Béchamel sauce – A simple roux with butter and flour, warmed milk, Dijon mustard, salt, pepper, and garlic powder forms the creamy base.
- Cheese – Sharp cheddar and a bit of Parmesan folded into the béchamel create a silky, flavorful cheese sauce.
Best Potatoes for Au Gratin Potatoes
Yukon Gold potatoes are semi-starchy and slightly waxy, which makes them ideal for au gratin. They have a buttery flavor and hold their shape when baked. Russets are starchier and can break down during baking, and they lack the natural creaminess of Yukon Golds.
Do You Peel Potatoes for Au Gratin Potatoes?
Yukon Golds have thin skins and do not need to be peeled. Leaving the skins on provides a rustic texture and helps the slices keep their shape. If you prefer a smoother appearance, you can peel them, but it’s optional.
How to Make Creamy Au Gratin Potatoes
This is an overview of the process; full measurements and step-by-step instructions follow in the recipe card below.
How to Thinly Slice Potatoes
- Slice the potatoes about 1/8-inch thick using a mandolin or a sharp knife.
- Set the slices aside while you prepare the cheese sauce.
Pro Tip
A mandolin ensures uniform, very thin slices for even cooking. A handheld mandolin is an inexpensive, space-saving option.
Make the Cheese Sauce
- Melt butter over low heat, add flour, and cook the roux for 3–4 minutes without browning.
- Whisk in warm milk a little at a time until smooth. Add Dijon mustard, then cook until the béchamel thickens. Remove from heat and season with salt and garlic powder.
- Stir in grated cheddar and Parmesan until melted and the sauce is smooth.
Assemble the Au Gratin Potatoes
- Sprinkle half the diced onion across the bottom of a prepared baking dish and drizzle with a small portion of the cheese sauce.
- Arrange a single layer of potato slices in rows, then add the remaining onion and seasoned salt.
- Pour the rest of the cheese sauce evenly over the potatoes, spreading to coat. Cover with foil and bake for 50 minutes. Remove foil and bake 30–35 more minutes until bubbly, browned, and fork-tender.
Pro Tip
Spray the underside of the foil with nonstick spray and place it coated side down when covering the dish. This helps keep cheese sauce from sticking to the foil.
Variations
- Cheese – Substitute part of the sharp cheddar with Gruyère, Monterey Jack, Havarti, or Gouda. Use freshly shredded cheese for the best melt and texture.
- Herbs – Finish with fresh thyme, chopped parsley, or chives for brightness before serving.
Make-Ahead Au Gratin Potatoes
You can assemble the casserole up to 24 hours ahead. After covering with cheese sauce, cover tightly with foil and refrigerate. Before baking, let the dish rest at room temperature for 30–60 minutes to take off the chill, then bake as directed.
How to Reheat Au Gratin Potatoes
- Microwave – Reheat individual portions uncovered for 2–3 minutes until warm.
- Oven – For larger portions, cover with foil and reheat at 375°F for about 20 minutes or until heated through.
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Creamy Au Gratin Potatoes
Ingredients
- 3 pounds Yukon Gold potatoes, peeled or unpeeled
- ½ teaspoon seasoned salt
- 1 cup diced sweet yellow onion
- minced fresh herbs like parsley or thyme leaves, optional garnish
Cheesy Bechamel Sauce
- 3 tablespoons butter
- 3 tablespoons flour
- 2 cups milk, warmed
- 1 teaspoon Dijon mustard
- 1 teaspoon salt
- ½ teaspoon garlic powder
- ¼ teaspoon freshly ground black pepper
- 1 ½ cup shredded cheddar cheese
- ½ cup shredded Parmesan cheese
Instructions
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Preheat oven to 400°F. Coat a 13×9-inch baking dish with nonstick spray.
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Thinly slice potatoes about 1/8-inch thick and set aside.
Make the Bechamel Cheese Sauce
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Melt butter over low heat and add flour, whisking for 3–4 minutes without browning. Gradually whisk in warm milk until smooth. Add Dijon and cook until thickened, keeping the heat low so it doesn’t boil. Remove from heat, stir in salt and garlic powder, then add cheeses and stir until melted.
Assemble the Au Gratin Potatoes
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Sprinkle half the onions on the bottom of the dish and drizzle with about 1/4 to 1/3 of the cheese sauce. Layer the potatoes, sprinkle the remaining onion and seasoned salt, then pour the remaining sauce over the top, spreading to cover.
Bake
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Spray the underside of a piece of foil with nonstick spray and cover the dish. Bake for 50 minutes. Remove foil and bake 30–35 more minutes until browned, bubbly, and the potatoes are fork tender. Let rest 5–10 minutes and garnish with fresh herbs if desired.
Notes
Thin-skinned Yukon Golds do not need peeling; leaving the skins adds rustic texture and helps slices keep their shape. Peel if you prefer a smoother presentation.
Variations
- Cheese – Try Gruyère, Monterey Jack, Havarti, or Gouda in place of part of the cheddar. Use freshly shredded cheese for best melt.
- Herbs – Garnish with fresh thyme, chopped parsley, or chives before serving.
Make-Ahead Tips
Assemble up to 24 hours ahead, cover with foil, and refrigerate. Let sit at room temperature 30–60 minutes before baking to remove chill.
Nutrition
Nutrition information is an estimate calculated from generic ingredients and should be used as a guideline.
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This post was originally published on March 23, 2016, and has been updated with new text and images.