Cheesy Au Gratin Potatoes

These au gratin potatoes feature thin-sliced potatoes layered with a rich, homemade cheese sauce and baked until golden and bubbling.

Skip the boxed version because homemade delivers far better flavor and texture with ingredients you likely already have.

Why You’ll Love It

• Creamy, cheesy comfort food at its finest
• No canned soup or processed cheese required
• Impressive enough for holidays, easy enough for weeknights
• The crispy top layer is the best part
• Reheats beautifully the next day
• Scales easily for a crowd

Ingredients

For the Potatoes

• 3 pounds (1.4 kg) Yukon Gold or Russet potatoes (about 6 medium)
• 1 teaspoon salt
• 1/2 teaspoon black pepper

For the Cheese Sauce

• 4 tablespoons (57g) unsalted butter
• 1/4 cup (32g) all-purpose flour
• 2 cups (480ml) whole milk, warmed
• 1 cup (240ml) heavy cream
• 2 cloves garlic, minced
• 1/2 teaspoon salt
• 1/4 teaspoon black pepper
• 1/4 teaspoon ground nutmeg
• 8 ounces (227g) sharp cheddar cheese, shredded (about 2 cups)
• 4 ounces (113g) Gruyere cheese, shredded (about 1 cup)

For the Topping

• 1/2 cup (55g) shredded cheddar cheese
• 2 tablespoons chopped fresh chives (optional)

Steps

1. Preheat the oven to 375°F (190°C).
2. Grease a 9×13-inch baking dish with butter.
3. Peel the potatoes and slice them 1/8-inch thick using a mandoline or sharp knife.
4. Consistent thickness is important for even cooking.
5. Place the sliced potatoes in a large bowl of cold water to prevent browning while you make the sauce.
6. Melt the butter in a large saucepan over medium heat.
7. Add the minced garlic and cook for 30 seconds until fragrant.
8. Whisk in the flour and cook for 1 minute, stirring constantly.
9. Slowly pour in the warm milk while whisking to prevent lumps.
10. Add the heavy cream and continue whisking.
11. Cook until the sauce thickens enough to coat the back of a spoon, about 5-7 minutes.
12. Remove from heat and stir in the salt, pepper, and nutmeg.
13. Add the cheddar and Gruyere cheeses and stir until completely melted and smooth.
14. Drain the potatoes thoroughly and pat dry with a clean kitchen towel.
15. Season the potatoes with 1 teaspoon salt and 1/2 teaspoon pepper.
16. Arrange one-third of the potato slices in the bottom of the prepared dish, overlapping slightly.
17. Pour one-third of the cheese sauce over the potatoes.
18. Repeat with two more layers of potatoes and sauce.
19. Press down gently on the top layer to ensure the potatoes are submerged in the sauce.
20. Sprinkle the reserved 1/2 cup of shredded cheddar over the top.
21. Cover tightly with aluminum foil.
22. Bake covered for 45 minutes.
23. Remove the foil and bake uncovered for an additional 25-30 minutes until the top is golden brown and the potatoes are tender.
24. Test doneness by inserting a knife into the center, which should slide through easily.
25. Let rest for 10 minutes before serving.
26. Garnish with fresh chives if desired.

Helpful Tips and Substitutions

Yukon Gold potatoes hold their shape better and have a creamier texture than Russets.

If using Russets, the dish will be slightly more starchy and thick.

A mandoline makes quick work of slicing, but a sharp knife and steady hand work fine.

Warming the milk before adding it to the roux prevents lumps and speeds up thickening.

Shred your own cheese from blocks since pre-shredded cheese contains anti-caking agents that affect melting.

No Gruyere? Use all cheddar or substitute with fontina or Swiss.

Add 4 strips of cooked, crumbled bacon between the layers for a loaded version.

For a lighter dish, use half-and-half instead of heavy cream.

Store your cheese grater in an easy-to-reach spot because freshly grated cheese makes a noticeable difference.

Serving Ideas

Serve alongside roasted chicken, grilled steak, or baked ham.

This dish pairs especially well with simple proteins that let the potatoes shine.

Add a green salad or steamed broccoli to balance the richness.

Scoop portions with a large spoon to get all the layers intact.

Leftovers make an excellent brunch side with eggs and bacon.

Make-Ahead and Storage

Assemble the entire dish up to 24 hours ahead and store covered in the refrigerator.

Add 15-20 minutes to the covered baking time if baking directly from the refrigerator.

Store leftovers in an airtight container in the refrigerator for up to 4 days.

Reheat individual portions in the microwave or in a 350°F oven until heated through.

Add a splash of milk when reheating to restore creaminess.

This dish does not freeze well because the cream sauce separates and the potatoes become grainy.

Better Than the Box

Once you make au gratin potatoes from scratch, the boxed version will never taste the same.

Yes, it takes more time, but the creamy sauce and real cheese flavor are worth every minute.

This is the side dish that people remember from holiday dinners.

A quality whisk helps you build a smooth sauce every time.