Cheesy Potato Gratin

Cheesy Potato Gratin combines thinly sliced yellow potatoes with a creamy homemade cheese sauce and a golden baked top. I leave the skins on the potatoes, which saves a little preparation—just give them a thorough wash before slicing.

We especially like this with sharp cheddar, Parmesan, and regular Swiss cheese. I’ve used Swiss in place of Gruyère and found that we prefer its flavor in this dish.

Thinly Sliced Potatoes and Plenty of Cheese

This Cheesy Potato Gratin is a comforting side dish made with yellow potatoes, heavy cream, garlic, and three cheeses. The potatoes bake in the sauce until tender, with a golden top and creamy layers underneath.

It takes some time in the oven, but the preparation is straightforward. Once the potatoes are sliced and the cheese sauce is ready, everything goes into the casserole dish in two layers.

Plan for approximately 90 minutes of baking, followed by 15 minutes of resting before serving.

Why I Use Yellow Potatoes for Cheesy Potato Gratin

I use yellow potatoes and leave the skins on for this recipe. Wash them thoroughly, checking for any dirt before slicing.

I find yellow potatoes have a sweeter, richer flavor than russets. That flavor blends nicely with the cheeses and helps the potatoes hold their own against the sauce. With russets, I find the cheese sauce can overpower the milder potato flavor.

Leaving the skins on means one less preparation step. If you prefer peeled potatoes, you can peel them, but it isn’t necessary for the way I make this dish.

Slice the potatoes approximately ⅛ inch thick, keeping them as even as possible. Similar thickness helps the slices cook at the same rate, so you’re less likely to have some tender pieces while others are still firm.

A sharp knife works, or you can use a mandoline with its hand guard if that’s your preferred tool.

Our Preference for Swiss Cheese

The cheese sauce combines sharp cheddar, Parmesan, and Swiss. I substituted regular Swiss for Gruyère, and we found that we liked it even better.

I use regular Swiss cheese—the kind with the larger holes—rather than baby Swiss. That’s the version I prefer for this recipe.

Gruyère remains an option, and additional cheddar can also be used in place of the Swiss. Choose the combination you enjoy, keeping the amounts the same.

Make the Cheese Sauce Gently

Start by melting the butter over medium-low heat. Add the minced garlic and cook briefly, stirring, before adding the heavy cream and seasonings.

You only need to heat the cream until it is steaming. Stir occasionally and avoid bringing it to a vigorous boil.

Remove the saucepan from the heat and add the cheeses one at a time. Stir each addition until melted before adding the next. This makes it easier to combine everything into a smooth sauce.

Have the cheeses shredded and measured before you begin so they’re ready when the cream is warm.

Layer the Cheesy Potato Gratin

Butter a standard 9x13x2-inch casserole dish. Arrange half the sliced potatoes evenly across the bottom, then pour half the cheese sauce over them.

Repeat with the remaining potatoes and sauce, distributing both as evenly as you can.

Leave at least ½ inch of space below the rim of the dish. The sauce will bubble while baking, so avoid filling the casserole all the way to the top. If necessary, put any excess into a separate small baking dish.

Put a Baking Sheet Underneath

Set the casserole dish on a foil-lined baking sheet before placing it in the oven. This helps catch any cheese sauce that bubbles over and makes cleanup easier.

The baking sheet is there to catch drips, so you should still leave room below the rim of the casserole dish.

It’s a simple step that’s worth doing before the dish becomes hot and difficult to move.

Bake Until the Center Is Tender

Cover the casserole tightly with foil and bake at 350°F for 60 minutes. Then remove the foil and continue baking for approximately 30 minutes.

Check the potatoes in the center with a knife. It should slide through easily without meeting firm slices. A golden top alone doesn’t mean the potatoes underneath are finished.

The baking time is an estimate. Thicker slices or a different baking dish can change how long the potatoes need. If the top is browned but the center still needs time, loosely cover it with foil and continue baking until tender.

Let the Cheesy Potato Gratin Rest Before Serving

Allow the gratin to stand for approximately 15 minutes after removing it from the oven. This gives the sauce time to thicken a little before you begin serving.

The finished dish should have tender potato layers coated in cheese sauce, with a golden surface. Serve it alongside your preferred main dish whenever you want a rich, comforting potato side.

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Cheesy Potato Gratin

Thinly sliced yellow potatoes baked in a creamy sauce with sharp cheddar, Swiss, and Parmesan. A rich, comforting side dish with tender potato layers and a golden cheese top.

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Prep Time 25 minutes mins

Cook Time 1 hour hr 30 minutes mins

Resting Time 15 minutes mins

Total Time 2 hours hrs 10 minutes mins

Servings: 10 servings

Course: Side Dish

Cuisine: American

Ingredients Equipment Method Notes

Ingredients

  

• 3 pounds yellow potatoes washed, unpeeled, and sliced 1/8 inch thick
• 1 1/2 tablespoons butter plus more for greasing the dish
• 2 –3 cloves garlic minced
• 2 cups heavy cream
• 1 teaspoon salt
• 1/2 teaspoon black pepper
• 3/4 teaspoon paprika
• 1 1/3 cups shredded sharp cheddar cheese
• 1/2 cup grated Parmesan cheese
• 1 cup shredded regular Swiss cheese or Gruyère or additional cheddar

Equipment

• 9×13 casserole dish
• baking sheet
• aluminum foil
• saucepan
• measuring cups & measuring spoons
• whisk or silicone spatula
• cutting board
• sharp knife
• Mandoline slicer with hand guard (optional)

Method

 

1. Preparing the Potatoes and Dish
2. Preheat the oven to 350°F. Butter a 9x13x2-inch casserole dish. Line a baking sheet with foil and set aside.
3. Thoroughly wash the potatoes. Leave the skins on and slice approximately 1/8 inch thick, keeping the slices as even as possible.
4. Making the Cheese Sauce
5. Melt the butter in a saucepan over medium-low heat. Add the minced garlic and cook for approximately 30 seconds, stirring.
6. Add the heavy cream, salt, pepper, and paprika. Heat until steaming, stirring occasionally. Remove from the heat.
7. Add the cheddar, Parmesan, and Swiss cheeses one at a time, stirring until each addition is melted before adding the next. Stir until the sauce is smooth.
8. Layering and Baking
9. Arrange half the potato slices evenly in the prepared casserole dish. Pour half the cheese sauce over the potatoes.
10. Arrange the remaining potatoes over the first layer and pour the remaining sauce evenly over them. Leave at least 1/2 inch of space below the rim. If necessary, place any excess in a separate small baking dish.
11. Cover tightly with foil. Set the casserole on the foil-lined baking sheet to catch any drips.
12. Bake for 60 minutes. Remove the foil and bake for approximately 30 minutes longer, until the top is golden and a knife slides easily through the potatoes in the center.
13. If the top browns before the potatoes are tender, loosely cover with foil and continue baking until done.
14. Let stand for 15 minutes before serving so the sauce can thicken slightly.

Notes

Potatoes: I prefer yellow potatoes for their sweeter, richer flavor. I find their flavor blends nicely with the cheese sauce without being overwhelmed by it.

Peeling: I leave the skins on. Wash the potatoes thoroughly before slicing. You may peel them if preferred.

Even slices: Aim for slices approximately 1/8 inch thick so the potatoes cook evenly. If using a mandoline, use its hand guard.

Swiss cheese: We prefer regular Swiss cheese—the kind with larger holes—rather than baby Swiss. Gruyère or additional sharp cheddar can be substituted in the same amount.

Dish capacity: Use a 9x13x2-inch casserole dish and leave at least 1/2 inch below the rim for bubbling. Bake any excess in a separate small dish rather than overfilling.

Catch drips: Place the casserole on a foil-lined baking sheet to catch any cheese sauce that bubbles over.

Baking time: Approximately 90 minutes is an estimate. The thickness of the potato slices and the baking dish can affect the cooking time. Check the center with a knife; the potatoes should be tender throughout.

Browning: If the top becomes golden before the potatoes are tender, loosely cover with foil and continue baking.

Resting: Let stand for 15 minutes before serving to allow the sauce to thicken slightly.

Servings: Makes approximately 10 side-dish servings, depending on portion size.