Scalloped Potatoes Au Gratin Recipe

If you’re looking for a rich, creamy, golden-topped Scalloped Potatoes Au Gratin Recipe that feels holiday-worthy but is easy enough for Sunday supper, this one is it.

A Cozy Classic That Never Goes Out of Style

There’s something about a bubbling pan of scalloped potatoes that brings people to the kitchen before you’ve even called them to dinner. This Scalloped Potatoes Au Gratin Recipe is that kind of dish—tender sliced potatoes layered in a velvety cream sauce, tucked under a blanket of melty cheese, and baked until the edges are beautifully browned and a little crisp. It’s humble food, yes, but it feels downright special.

Now, technically, “scalloped potatoes” and “potatoes au gratin” aren’t always the exact same thing. Traditional scalloped potatoes often lean more on cream, while potatoes au gratin usually include cheese. But in many American kitchens, the names blend together, and honestly, most of us are just after one thing: a pan of cheesy potatoes that’s creamy, comforting, and worth going back for seconds. Maybe thirds.

I love serving this baked potato dish at Easter, Thanksgiving, Christmas dinner, and those chilly Sunday family meals when roast chicken or ham is on the table. It also works beautifully for a potluck because it travels well and holds its heat longer than you’d think. And while I wouldn’t call it “light” exactly, I will say this: making it from scratch gives you better flavor, better texture, and more control over the ingredients than anything from a box. That’s a win in my book.

Why You’ll Love This Recipe

• Creamy, cheesy, and deeply satisfying
• Made with simple grocery-store ingredients
• Perfect for holidays, potlucks, and weeknight dinners
• Great make-ahead side dish recipe for busy cooks
• Bakes up golden and gorgeous every time
• Easy to customize with different cheeses and seasonings
• Feeds a crowd without feeling fussy
• Pairs well with ham, roast beef, chicken, or pork
• Tastes even better the next day
• A true comfort food recipe that everybody recognizes

Ingredients You’ll Need

Here’s everything you need for this homemade potato casserole. I’m giving exact measurements, along with a few little kitchen notes that help the dish turn out beautifully.

• 2 1/2 pounds Yukon Gold potatoes (about 6 to 8 medium potatoes, peeled and sliced 1/8-inch thick)

  • Yukon Golds are my favorite here because they stay creamy and hold their shape. Russets work too and create a softer, starchier texture.

• 2 tablespoons unsalted butter

  • Use this for greasing the baking dish and starting the sauce. Salted butter is fine; just reduce added salt a touch.

• 1 small yellow onion, very thinly sliced

  • Adds sweetness and depth without overpowering the potatoes.

• 2 cloves garlic, minced

  • Fresh garlic gives the best flavor. Garlic powder works in a pinch—use about 1/2 teaspoon.

• 3 tablespoons all-purpose flour

  • This thickens the cream sauce so your gratin potatoes slice nicely instead of turning soupy.

• 2 cups whole milk

  • Whole milk gives that classic creamy texture. For a richer result, use 1 cup milk and 1 cup half-and-half.

• 1 cup heavy cream

  • This is what makes the sauce feel luxurious. If needed, you can substitute half-and-half, though the sauce will be a bit lighter.

• 1 teaspoon kosher salt

  • Potatoes need seasoning, so don’t be shy here.

• 1/2 teaspoon black pepper

• 1/4 teaspoon ground nutmeg

  • Just a pinch gives the sauce a warm, old-fashioned flavor. It’s subtle, but lovely.

• 1 teaspoon fresh thyme leaves (or 1/2 teaspoon dried thyme)

  • Optional, but it adds a gentle herbal note that works so well with creamy potatoes.

• 1 1/2 cups shredded sharp cheddar cheese

  • Sharp cheddar gives bold flavor and that familiar cheesy pull.

• 1 cup shredded Gruyère cheese

  • Gruyère melts beautifully and gives the dish that classic au gratin recipe flavor. Swiss is a decent substitute if that’s what you have.

• 1/4 cup grated Parmesan cheese

  • For a savory, golden top.

• Cooking spray or extra butter for the baking dish

Directions

1. Prep the oven and dish.
   Preheat your oven to 375°F. Grease a 9×13-inch baking dish with butter or cooking spray. If you’ve got a ceramic or cast-iron-style baking dish, even better—it holds heat beautifully and helps the edges caramelize.

2. Slice the potatoes evenly.
   Peel the potatoes and slice them about 1/8 inch thick. A mandoline makes this job much easier and gives even slices, which means even cooking. If slicing by hand, take your time and keep the thickness consistent.

3. Start the sauce.
   In a medium saucepan over medium heat, melt the butter. Add the sliced onion and cook for 4 to 5 minutes, until softened. Stir in the garlic and cook for about 30 seconds, just until fragrant. Don’t let it brown.

4. Make the creamy base.
   Sprinkle the flour over the onions and stir constantly for 1 minute. Slowly whisk in the milk and heavy cream. Keep whisking so you don’t get lumps. Add the salt, pepper, nutmeg, and thyme, then simmer gently for 3 to 5 minutes until the sauce thickens enough to lightly coat the back of a spoon.

5. Add some of the cheese.
   Remove the pan from the heat and stir in 1 cup cheddar and 3/4 cup Gruyère. Stir until smooth and melty. This gives you that rich cheese potato bake texture right from the start.

6. Layer the potatoes.
   Arrange half of the sliced potatoes in the prepared baking dish, overlapping them slightly. Pour over about half the sauce. Add the remaining potatoes, then pour the rest of the sauce evenly over the top. Use a spoon or offset spatula to nudge the sauce into the corners.

7. Top it off.
   Sprinkle the remaining cheddar, Gruyère, and all the Parmesan over the top. Cover loosely with foil. If your cheese tends to stick, spray the underside of the foil lightly first. It’s one of those tiny tricks that saves a lot of aggravation.

8. Bake until tender.
   Bake covered for 45 minutes. Then remove the foil and bake for another 25 to 35 minutes, until the top is golden brown and the potatoes are fork-tender. If you slide a knife into the center and it meets little resistance, you’re there.

9. Let it rest before serving.
   This part matters more than people realize. Let the dish rest for 10 to 15 minutes before serving. The sauce settles, the layers firm up, and the whole thing becomes much easier to scoop neatly.

Servings & Timing

• Yield: 8 to 10 servings
• Prep Time: 25 minutes
• Bake Time: 70 to 80 minutes
• Rest Time: 10 to 15 minutes
• Total Time: About 1 hour 50 minutes

If you’re making this for a holiday menu, plan on closer to 2 hours from start to finish when you count peeling, slicing, baking, and resting.

Variations to Make It Your Own

This homemade au gratin is wonderfully flexible. Here are a few easy ways to change it up:

• Add cooked bacon: Sprinkle crumbled bacon between the layers for smoky flavor.
• Use sweet onions or shallots: They add a gentler, slightly sweeter taste.
• Try different cheeses: Fontina, Monterey Jack, or white cheddar all melt nicely.
• Make it ham-friendly: Add diced cooked ham for a hearty one-pan meal.
• Go extra herby: Add rosemary or chives for a more fragrant finish.
• Lighten it slightly: Swap part of the cream for more milk, though the sauce will be less rich.

Storage & Reheating

Leftover oven baked potatoes keep surprisingly well, which is one more reason I make a full pan whenever I can.

• Refrigerator: Store cooled leftovers in an airtight container or tightly covered dish for up to 4 days.
• Freezer: Freeze portions for up to 2 months. The texture may soften a little after thawing, but the flavor stays very good.
• Reheating: Warm individual portions in the microwave in 60-second bursts, or reheat the full dish covered in a 350°F oven until hot, about 20 to 25 minutes.
• Make-ahead tip: Assemble the dish up to 24 hours ahead, cover, and refrigerate. Let it sit at room temperature for about 30 minutes before baking. You may need to add 10 extra minutes to the baking time.

Notes From My Kitchen

After testing this recipe a few ways, I can tell you a few little things made the biggest difference.

First, slice the potatoes thin and evenly. Sounds obvious, I know, but it’s the difference between perfectly tender layers and that frustrating half-done center. A mandoline is worth pulling out for this recipe, even if you don’t use it often.

Second, don’t skip simmering the sauce before assembling the dish. Some recipes have you pour plain cream over the potatoes and call it a day, and yes, that can work. But a pre-thickened sauce gives you a more reliable, creamy result. It’s the difference between a casserole that slices beautifully and one that spreads all over the plate.

Third, let it rest. I’m repeating myself, but it matters. Those 10 to 15 minutes let the starch from the potatoes and the cheese in the sauce settle into each other—kind of like guests finding their seats before dinner really gets going.

And one last thing: if you want a deeper golden top, pop it under the broiler for 1 to 2 minutes right at the end. Just don’t wander off. Cheese under a broiler can go from gorgeous to “well, bless it” in a heartbeat.

FAQs

Can I make scalloped potatoes au gratin ahead of time?

Yes, absolutely. Assemble the dish up to a day ahead, refrigerate it, and bake when needed. Add a few extra minutes if it’s still cold from the fridge.

What are the best potatoes for this Scalloped Potatoes Au Gratin Recipe?

Yukon Golds are my top choice because they stay creamy and hold their shape well. Russets are softer and starchier, which some folks really enjoy.

Why is my sauce too thin?

Usually, it means the sauce wasn’t thickened enough on the stovetop or the dish didn’t rest after baking. A short rest helps the sauce settle and firm up.

Can I use pre-shredded cheese?

You can, but freshly shredded cheese melts more smoothly. Pre-shredded cheese often contains anti-caking agents that can make the sauce a bit grainy.

How do I know when the potatoes are done?

Insert a knife into the center of the casserole. If it slides through easily with little resistance, the potatoes are tender and ready.

Can I make this without onions?

Yes. You can leave them out if needed, though they add wonderful flavor. A small pinch of onion powder can help make up for it.

Why did my potatoes turn gray?

That usually happens when raw sliced potatoes sit out too long. If you need to prep ahead, keep them in cold water, then dry them well before layering.

What should I serve with this baked potato dish?

It’s wonderful with glazed ham, roast turkey, pork loin, beef roast, or even a simple green salad if you want balance on the plate.

Conclusion

This Scalloped Potatoes Au Gratin Recipe is creamy, cheesy, golden on top, and exactly the kind of comfort food recipe that makes a dinner table feel warm and welcoming. It’s reliable enough for holidays, easy enough for family meals, and delicious enough that nobody ever seems to leave leftovers behind for long.

If you give it a try, I’d love to hear how it turned out for you. Leave a comment, share your favorite cheese blend, or save this recipe for your next holiday menu—and if you’re planning the full meal, pair it with your favorite roast and a crisp green vegetable for a plate that really sings.