When I’m craving comfort that feels a little fancy, I turn to this easy au gratin potatoes. Tender, thinly sliced potatoes bathe in a silky, cheesy cream sauce, then bake to golden, bubbly perfection. Every forkful is rich, cozy, and totally satisfying.
I make these potatoes au gratin every holiday season because they strike that perfect balance between indulgent and effortless. The layers of thinly sliced Yukon Gold potatoes soak up a rich, garlicky cream sauce made from butter, milk, and a blend of cheddar, Gruyere, and Parmesan. The cheeses melt together into a silky sauce that bubbles and browns beautifully in the oven. It’s the kind of side dish that feels fancy but couldn’t be simpler to pull off.
Tips for Beginners
- Slice the potatoes evenly. If your slices are thicker than about ⅛ inch, the centers may stay firm while the edges soften. To fix this, either slice the potatoes thinner (a mandoline makes this quick and consistent) or extend the covered bake time by 10–15 minutes. The goal is fork-tender potatoes before you uncover them for browning.
- If you’re short on time. Wrap the baking pan (non-metal only!) in plastic wrap before adding the cheese sauce, microwave on high for 10 minutes, remove the plastic wrap, add the cheese sauce, and bake as directed for about 40-45 minutes.
- Watch the broil. Broilers vary, so keep a close eye during that last minute. Move the dish to a lower oven rack if it’s browning too quickly, or tent loosely with foil for the final few minutes to protect the top while the center finishes cooking.
- For melty cheese. If the sauce looks oily or clumpy, the heat was likely too high. Always remove the pan from the burner before adding cheese, and stir slowly to let it melt evenly. You can even add a splash of milk or cream to bring it back together if it starts to separate.
Au Gratin Potatoes Recipe
Equipment
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9×13 Baking Pan
Ingredients
- 3 lbs Yukon Gold potatoes thinly sliced (about 12 potatoes)
- ½ yellow onion thinly sliced
- 4 tbsp unsalted butter (½ stick) plus more for greasing the pan
- 2 cloves garlic minced
- ¼ cup all-purpose flour
- 1½ cups whole milk
- 1 tsp kosher salt
- ½ tsp ground black pepper
- 1 cup freshly shredded cheddar cheese
- 1½ cups freshly shredded gruyere cheese divided
- ½ cup freshly grated Parmesan cheese
Instructions
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Preheat oven to 350°F. Grease a 9×13-inch baking pan with butter.
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Layer the potatoes and onions in the baking dish. Set aside.
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In a medium saucepan, melt the butter over medium heat. Add in the garlic and cook until fragrant.
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Sprinkle over the flour and whisk until smooth and the flour is golden, about 1 minute.
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Slowly pour in the milk while whisking, making sure to quickly whisk out any lumps. Bring to a simmer.
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Remove from the heat and whisk in the salt, pepper, cheddar, and ¾ cup gruyere until melted. Pour over the potatoes.
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Cover with foil and bake for 45-60 minutes, or until the potatoes are tender when pierced with a knife in the center of the baking dish.
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Remove the foil and sprinkle on the remaining gruyere and parmesan cheese. Bake for 15-20 minutes until the cheese is melted and bubbly.
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Optional: To brown the cheese, broil for 1-2 minutes.
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Garnish with herbs and serve.
Video
Notes
- Shred your own cheese from a block for the smoothest sauce. Pre-shredded cheese is coated in starches that can cause the sauce to become grainy!
- A runny sauce usually means it didn’t simmer long enough to activate the roux. Let it bubble gently for a few extra minutes until it thickens to coat the back of a spoon. If it’s still thin, whisk 1 tsp of flour into 2 tbsp of warm milk and stir it in.
Nutrition
How to Make Au Gratin Potatoes Step by Step
Layer the potatoes and onions: Preheat oven to 350°F. Grease a 9×13-inch baking pan with butter. Layer 3 lbs of thinly sliced Yukon Gold potatoes and half of a thinly sliced yellow onion in the baking dish. Set aside.
Melt the butter: In a medium saucepan, melt 4 tbsp of unsalted butter over medium heat. Add in 2 cloves minced garlic and cook until fragrant.
Thicken the roux: Sprinkle over ¼ cup of all-purpose flour and whisk until smooth and the flour is golden, about 1 minute.
Thin the sauce: Slowly pour in 1½ cups whole milk while whisking, making sure to quickly whisk out any lumps. Bring to a simmer.
Add the cheese: Remove from the heat and whisk in 1 tsp kosher salt, ½ tsp ground black pepper, 1 cup shredded cheddar, and ¾ cup shredded gruyere until melted. Pour over the potatoes.
Bake the Casserole: Cover with foil and bake for 45-60 minutes, or until the potatoes are tender when pierced with a knife in the center of the baking dish.
Brown the casserole: Remove the foil and sprinkle on the remaining ¾ cup of shredded gruyere and ½ cup grated parmesan cheese. Bake for 15-20 minutes until the cheese is melted and bubbly. To brown the cheese, broil for 1-2 minutes. Garnish with herbs and serve.
Variations on Potatoes Au Gratin
- You can use red potatoes in place of Yukon Gold.
- Feel free to switch up the cheese. Some other great cheeses include Swiss, fontina, Havarti, gouda, or mozzarella.
- Try adding 6-8 ounces of chopped cooked bacon or ham!
- Try adding 1-2 teaspoons of fresh herbs to the cheese sauce.
- Try topping your casserole with breadcrumbs or crumbled Ritz crackers.
How to Store and Reheat
Store leftover au gratin potatoes in an airtight container in the refrigerator for up to 5 days. Reheat in a 350°F oven covered with foil for about 20 minutes, or until hot.
Freeze au gratin potatoes in individual portions in airtight containers for up to 2 weeks. Let thaw overnight in the refrigerator before reheating.
To make ahead, assemble (without final cheese on top), cover tightly, and refrigerate overnight. When baking, add an extra 10–15 minutes under foil before proceeding to the cheese stage.
Serving Suggestions
Potatoes au gratin are the ultimate creamy, cheesy side dish for any holiday feast. They’re the kind of comfort food that feels special enough for a celebration, whether it’s Thanksgiving, Christmas, or Easter. I especially love how they pair beautifully with just about any holiday main dish—from juicy turkey and glazed ham to an elegant beef tenderloin or roast.
Our Au Gratin Potatoes recipe was originally published 11/20/22. It was retested, reworked, and republished to be better than ever 11/7/25.
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