Potato Gratin – Classic Creamy Cheesy Comfort

Potato Gratin is the ultimate melt-in-your-mouth side dish made with thinly sliced potatoes layered in a rich, creamy cheese sauce and baked until golden and bubbling. This classic comfort food transforms simple ingredients into something elegant enough for holidays yet easy enough for Sunday dinner.

If you love tender potatoes wrapped in velvety sauce with perfectly browned cheese on top, Potato Gratin will quickly become your go-to recipe. Every layer soaks up creamy goodness while the top develops that irresistible golden crust.

The first time I made Potato Gratin from scratch, I expected it to be complicated. I had always relied on boxed mixes during busy weeks. However, once I whisked together the simple béchamel sauce and layered the potatoes by hand, I realized how much better homemade tastes. As it baked, the aroma of butter, garlic, thyme, and cheese filled the kitchen. When I finally sliced into it and saw the creamy layers hold together perfectly, I knew I would never go back to store-bought versions again.

Classic Potato Gratin with thinly sliced potatoes baked in a creamy cheese sauce until golden and tender.

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Course: Side Dish

Cuisine: French

Calories: 341

Ingredients Equipment Method Nutrition Notes

Ingredients

  

• 3 tablespoons butter
• 1 small onion, finely diced
• 1 clove garlic, minced
• 1 teaspoon thyme, chopped
• 3 tablespoons flour
• 1 1/2 cups milk
• 1 1/2 cups gruyere cheese, shredded
• 1 pinch nutmeg
• 4 pounds potatoes, thinly sliced

Equipment

• saucepan
• Baking Dish
• Mandoline slicer

Method

 

1. Melt butter in saucepan. Cook onion until tender. Add garlic and thyme.
2. Stir in flour and cook briefly. Whisk in milk and cook until thickened.
3. Stir in half the cheese until melted. Season with nutmeg, salt and pepper.
4. Layer potatoes with sauce in baking dish. Top with remaining cheese.
5. Bake at 350°F for 45-60 minutes until tender and golden.

Nutrition

Calories: 341kcalCarbohydrates: 45gProtein: 11gFat: 13gSaturated Fat: 7gTrans Fat: 0.4gCholesterol: 37mgSodium: 170mgPotassium: 900mgFiber: 5gSugar: 4gVitamin A: 450IUVitamin C: 20mgCalcium: 220mgIron: 2mg

Notes

Slice potatoes evenly for best results. Let rest 10 minutes before serving. Substitute heavy cream for milk and flour if desired.

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Why You'll Love This Potato Gratin

Creamy, Cheesy Perfection

Potato Gratin stands out because of its luxurious texture. Thin slices of potato bake slowly in a creamy sauce that thickens as it cooks. Meanwhile, shredded cheese melts into the sauce and forms a golden crust on top.

The combination of butter, onion, garlic, thyme, and nutmeg builds subtle depth. The cheese adds richness without overwhelming the natural flavor of the potatoes.

Because the sauce coats every slice, each bite feels indulgent yet balanced.

Perfect for Holidays and Everyday Meals

Potato Gratin feels special enough for Thanksgiving, Christmas, or Easter. At the same time, it pairs beautifully with roasted chicken, steak, or ham for a simple weeknight dinner.

You can prepare it ahead of time and reheat it before serving. That flexibility makes it ideal when hosting guests.

Key Ingredients for Potato Gratin

The Potatoes

Use starchy or all-purpose potatoes for the best results.

• Russet potatoes create a softer, creamier texture.
• Yukon Gold potatoes provide a buttery flavor and hold their shape slightly better.

Slice the potatoes thinly and evenly. A mandoline slicer makes this step easier and ensures consistent cooking.

The Cream Sauce

This Potato Gratin uses a simple béchamel-style sauce made with:

• Butter
• Onion
• Garlic
• Thyme
• Flour
• Milk (or heavy cream)
• Nutmeg
• Salt and pepper

The flour thickens the milk into a smooth, creamy sauce. You can substitute heavy cream and skip the flour for an even richer version.

The Cheese

Gruyere cheese offers nutty, slightly sweet flavor and melts beautifully. However, you can substitute:

• Swiss
• Mozzarella
• Cheddar
• Havarti

You can also combine cheeses for extra depth. Adding Parmesan or Asiago enhances sharpness and complexity.

How to Make Potato Gratin Step by Step

Step 1: Prepare the Sauce

Melt butter in a saucepan over medium heat.

Add diced onion and cook until tender, about 3 to 5 minutes. Stir in garlic and thyme, cooking until fragrant.

Sprinkle in flour and stir continuously for about one minute until lightly golden.

Gradually whisk in milk. Cook until the sauce thickens, about 1 to 2 minutes.

Reduce heat and stir in half of the shredded cheese until melted. Add a pinch of nutmeg and season with salt and pepper.

Step 2: Layer the Potatoes

Spread a thin layer of sauce on the bottom of a baking dish.

Arrange a layer of thinly sliced potatoes over the sauce. Spoon more sauce on top. Continue layering potatoes and sauce until everything is used.

Pour any remaining sauce evenly over the top. Sprinkle with the remaining cheese.

Step 3: Bake to Perfection

Bake at 350°F (180°C) for 45 to 60 minutes.

The potatoes should be tender when pierced with a knife. The top should turn golden and slightly crisp around the edges.

Let the Potato Gratin rest for 10 minutes before slicing to allow the sauce to set.

Tips for the Best Potato Gratin

Slice Evenly

Uniform slices ensure even cooking. Thick slices may remain firm while thin ones overcook.

Don't Skip Seasoning

Potatoes require adequate salt to bring out their flavor. Season the sauce properly before layering.

Let It Rest

Resting allows the sauce to thicken further, making clean slices easier to serve.

Make It Ahead

You can assemble Potato Gratin up to a day in advance. Cover and refrigerate, then bake when ready.

Delicious Variations

Potato Gratin adapts easily to different flavors.

• Add cooked bacon for a smoky twist.
• Stir in sautéed mushrooms for earthy depth.
• Mix in caramelized onions for sweetness.
• Add a touch of mustard powder or cayenne for extra warmth.

You can even layer sweet potatoes with russets for a unique variation.

Storage and Reheating

Store leftover Potato Gratin in an airtight container in the refrigerator for up to 4 days.

Reheat in a 325°F oven until warmed through. Cover loosely with foil to prevent over-browning.

Although you can freeze it, the texture may soften slightly upon reheating.

Frequently Asked Questions

Can I use heavy cream instead of milk?

Yes. Replace the milk and flour with heavy cream for a richer version.

How thin should I slice the potatoes?

Slice about 1/8 inch thick for even cooking.

Can I make it gluten-free?

Yes. Use gluten-free flour or skip the flour and use heavy cream instead.

Why is my sauce too thick?

If the sauce thickens too much, whisk in a splash of milk before layering.

How do I know when it's done?

Insert a knife into the center. It should glide easily through the potatoes.

Conclusion

Potato Gratin transforms humble potatoes into a rich, creamy, crowd-pleasing side dish. With tender layers, melted cheese, and a golden crust, it delivers classic comfort in every bite.

Because it uses simple ingredients and straightforward steps, Potato Gratin remains approachable yet impressive. Whether you serve it at a holiday table or alongside a weeknight roast, this timeless dish always earns rave reviews.