The Recipe Bench

Prep Time: 30 minutes | Cook Time: 90 minutes | Total Time: 2 hours | Servings: 4

These Creamy Au Gratin Potatoes are the ultimate comfort food! Thinly sliced potatoes layered with sweet onions and smothered in a rich, creamy cheese sauce. Baked until golden and bubbly, this classic French dish is perfect for Thanksgiving, Christmas, or any special occasion. My husband considers it a celebration every time I make these!

Why You’ll Love This Recipe

Restaurant-quality at home. This tastes like something from a fancy steakhouse, but it’s surprisingly easy to make.

Rich and creamy cheese sauce. Made from scratch with a classic roux, milk, and sharp cheddar. No canned soup here!

Tender, melt-in-your-mouth potatoes. Thinly sliced potatoes become incredibly tender and soak up all that cheesy goodness.

Perfect for special occasions. This is the side dish that makes any meal feel like a celebration.

Make it ahead friendly. Assemble in advance and bake when ready. Perfect for Thanksgiving prep!

Tips for Success

Slice potatoes thinly and evenly. Use a mandoline slicer if you have one for perfectly uniform 1/4-inch slices. This ensures even cooking.

Use freshly shredded cheese. Pre-shredded cheese has anti-caking agents that prevent smooth melting. Fresh-shredded cheese makes the creamiest sauce.

Add milk gradually. This is the secret to a lump-free sauce. Pour it in slowly and whisk constantly.

Don’t skip the onions. They add a sweet, savory depth that makes this dish special.

Use sharp white cheddar for lighter color. If you want a lighter-colored sauce, use sharp white cheddar instead of yellow.

Check for doneness. Insert a fork or knife into the center. If it slides through easily, the potatoes are done.

Let it rest. Those 10 minutes of resting time help the sauce set up and make serving much easier.

Double for a crowd. Use a 9×13-inch dish and double all ingredients. Baking time stays about the same.

Frequently Asked Questions

Can I use a different type of potato? Russet potatoes work best because they’re starchy and absorb the sauce beautifully. Yukon Golds also work well and have a buttery flavor.

Why is my sauce lumpy? Add the milk gradually and whisk constantly. If lumps form, use an immersion blender to smooth it out.

Can I make this without onions? Yes, but the onions add great flavor. If you skip them, consider adding garlic or shallot for flavor.

Why is my dish watery? Make sure the sauce is thick before pouring it over the potatoes. Also, let it rest 10 minutes after baking so the sauce can set.

Can I use milk alternatives? Whole milk works best, but you can use half-and-half or cream for an even richer dish. Avoid low-fat milk as it won’t be as creamy.

How do I prevent the cheese from being grainy? Remove the pan from heat before adding cheese, and stir gently until melted. High heat can cause cheese to separate and become grainy.

Creamy Au Gratin Potatoes

Thinly sliced potatoes layered with sweet onions and smothered in a rich, creamy cheese sauce. Baked until golden and bubbly, this classic French dish is perfect for Thanksgiving, holidays, or any special occasion. This recipe makes enough for a small gathering, but easily double it for a crowd.

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Prep Time 30 minutes mins

Cook Time 3 hours hrs 30 minutes mins

Servings: 4 people

Ingredients Method

Ingredients

  

For the Base:

• 4 medium russet potatoes peeled and thinly sliced (1/4 inch or thinner)
• 1 medium onion sliced into rings
• Salt and ground black pepper to taste

For the Bechamel Sauce:

• 3 tablespoons butter
• 3 tablespoons all-purpose flour
• 1/2 teaspoon salt
• 2 cups whole milk
• 1 1/2 cups shredded sharp cheddar cheese freshly shredded

Method

 

1. Preheat and prep. Preheat your oven to 400°F. Grease a 2-quart (9×9-inch) casserole dish with butter.
2. Layer the potatoes. Arrange half of the sliced potatoes in the bottom of the prepared dish in an even layer.
3. Add the onions. Layer the onion rings over the potatoes, then top with the remaining potato slices. Season generously with salt and pepper.
4. Make the roux. Melt the butter in a medium saucepan over medium heat. Whisk in the flour and 1/2 teaspoon salt. Cook, whisking constantly, until the mixture is bubbly and the raw flour smell is gone, about 1 minute.
5. Add the milk gradually. Slowly pour in the milk, about 1/4 cup at a time, whisking well after each addition to prevent lumps. This gradual addition is key to a smooth sauce!
6. Thicken the sauce. Continue cooking, whisking constantly, until the mixture thickens enough to coat the back of a spoon, 3-5 minutes.
7. Add the cheese. Remove from heat and stir in the shredded cheddar cheese all at once. Stir constantly until the cheese is completely melted and the sauce is smooth, 30-60 seconds.
8. Pour over potatoes. Pour the cheese sauce evenly over the layered potatoes, making sure to cover as much as possible.
9. Cover and bake. Cover the dish tightly with aluminum foil. Bake in the preheated oven for 1 hour and 30 minutes, or until the potatoes are fork-tender and the sauce is bubbling.
10. Rest and serve. Let the casserole rest for 10 minutes before serving. This allows the sauce to thicken slightly and makes it easier to serve.

Nutrition Information (Per Serving)

Calories: 500 Protein: 20g Carbohydrates: 49g Fat: 25g Fiber: 4g Sugar: 7g

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