Creamy Potato Gratin [Video]

Catalina Castravet
By Catalina Castravet
5 from 6 reviews

Casserole Christmas Recipes Easter Side Dishes Thanksgiving Recipes Vegetarian

Cook time Cook time: 1 hour 30 minutes

25Potato Gratin combines French and Italian flavors in the most delicious, easy to make, and comforting potato dish. Thinly sliced potatoes are cooked in a creamy and irresistible Alfredo sauce till perfectly golden brown!

We love making easy side dishes that would be great for parties or day-to-day dinners. Other reader favorites include Bacon Ranch and Cheese Mashed Potatoes, Instant Pot Mashed Sweet Potatoes, and Cheesy Scalloped Potatoes.

Creamy Au Gratin Potatoes Recipe

This Potato Au Gratin Casserole is my new way of serving delicious potatoes for Christmas dinner or holidays! It is the ultimate comfort food that is full of flavors and cooked in a delicious creamy sauce till golden brown. This indulgent potato side dish was adapted it from Julia Child’s original recipe.

I like making it with either parmesan or mozzarella cheese. Over the year, I found that the parmesan cheese mixture really elevates the flavors resulting in ultra-tender potatoes. However, feel free to use different cheeses or your favorite types. Great alternatives would be cheddar cheese, sharp cheddar, or even gruyere cheese. 

Also, this recipe is also incredibly easy to make, especially if you have a mandoline to slice the spuds. Everyone who tried this dish was amazed and fell in love with the amazing Italian and French flavors it packs. Give this recipe a try, as it is guaranteed to be everyone’s favorite side dish for dinners or holidays!

What is Potato Gratin?

Also known as Dauphinoise Potatoes, this is a classic French cuisine and a side dish made with layers upon layers of finely sliced potatoes, heavy cream or milk, butter, and plenty of cheese!

Nowadays, the au gratin technique is widely used worldwide where an ingredient is thinly sliced, usually layered, and topped with a browned crust made of grated cheese, or a sauce. This technique can be applied to other ingredients apart from potatoes as well. 

Is it the same as dauphinoise?

The main difference is that the potato gratin is usually made using pre-cooked potatoes, that are cooked in cream and topped with cheese. While Gratin Dauphinoise is made of thinly sliced and not pre-cooked spuds that cook in cream.

Why You’ll Love These creamy potatoes:

  • First, it’s bursting with flavor and coated in the most delicious cheesy and creamy sauce.
  • Also, it’s incredibly easy to make and perfect for a large crowd or special occasion.
  • Hearty and tasty it can be served as a side dish or a vegetarian meal accompanied by a salad.
  • In addition, leftovers are delicious.
  • A favorite at Thanksgiving, Christmas, or Easter dinner.
  • Easy to take to a party.

How to make Potato Gratin?

For a step-by-step tutorial, watch the recipe video attached. But the general steps are as follows:

  1. Preheat oven: First, preheat the oven to 375 degrees F. 
  2. Prepare the Potatoes: Next, clean, and peel potatoes. Then, using an inexpensive mandoline slicer, thinly slice the spuds. You can also use pre-cooked potatoes, this will reduce the baking time in half.
  3. Make the Creamy Cheese Sauce: Then, in a large saucepan over medium-low heat, melt butter. Follow the recipe card instructions to make the Bechamel sauce. It is simply made by creating a roux using all-purpose flour, and after that adding the milk, cheese, and seasoning.
  4. Combine: After that, pour the cream mixture over the potatoes and combine them together. Then, transfer them into a prepared baking dish and bake till golden brown and crisp edges. 
  5. Serve: Enjoy them warm!

Best kind of potatoes to use:

For the best results, go with starchy potatoes. You want the spuds to get soft and tender when cooked with the cream sauce. Therefore, go with russet potatoes, king Edward, or Yukon gold, or Dutch creams. 

Why does my potato gratin curdle?

The main reason for curdling is caused by cooking the dish at high heat. I bake the casserole at 375 degrees F, and to keep it together, it is best to tackle it before it goes into the preheated oven. 

Also, do not use old potatoes and do not soak them for too long. The liquid from the potatoes will lower the fat content from the milk mixture. This will cause the spuds to get spongy to the point where they absorb too much water and don’t have enough fat, which might cause them to curdles as well. 

What to serve with it?

This is the perfect side dish to serve with:

How to store potato gratin?

  • Serve: After cooking, serve them right away. It will stay good at room temperature for up to 3 hours. 
  • Store: To store leftovers, transfer them to an airtight container. Then, refrigerate them in the fridge for 3-5 days. 
  • Freeze: Transfer the mixture to a buttered 9-by-13-inch freezer-to-oven baking dish. Then, cover tightly with aluminum foil. Freeze for up to 3 months.
  • Reheat: Place into a casserole dish and bake frozen and covered with foil, at 350°F, for up to 30 minutes, or until fully warm. 

More comforting side dishes:

Recipe Tips:

  • The homemade Italian seasoning is key here because it’s what will give the sauce that amazing aroma. Hence, don’t be shy about using it.
  • Also, I recommend using full-fat cream or whole milk. Because, in a recipe that is so cheesy and creamy, you really don’t want to take shortcuts or cutting calories.
  • Remember to slice the potatoes thinly, but not paper-thin. Hence, a mandolin slicer would be very helpful.
  • In addition, if you prefer the sauce spicier, you can add some cayenne pepper, taste, and adjust.
  • Other delicious mix-ins would be bacon crumbs or jalapeno peppers.
  • Use full-fat mozzarella cheese for the most luxurious creamy texture.

Tools used to make this recipe:

  • Mandoline – a lifesaver when it comes to slicing veggies
  • 9×9 inch pan – I use it for many recipes, brownies, fudge, and blondies. Its quality is great and I like the perfect measurements, it works great for smaller batch recipes.

Potato Gratin

Creamy Potato Gratin

Potato Gratin combines is a comforting side dish made with thinly sliced potatoes, and cooked in a creamy Alfredo sauce till golden brown! 🥔
5 from 6 votes
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Prep Time: 15 minutes
Cook Time: 1 hour 30 minutes
Total Time: 1 hour 45 minutes
Servings: 8 servings
Calories: 251kcal
Author: Catalina Castravet


  • 5 tablespoons unsalted butter
  • 1 medium onion (finely chopped)
  • 1/4 cup all-purpose flour
  • 1/2 teaspoon coarse salt
  • 1 teaspoon Italian Seasoning
  • 1/2 teaspoon black pepper
  • 4 cups whole milk
  • 2 1/2 cups mozzarella cheese or parmesan cheese (shredded)
  • 6 cups thinly sliced peeled potatoes (about 5-6 medium potatoes)


  • First, preheat the oven to 375 degrees F.
  • Grease a 9x13 inches deep baking dish and set it aside.

Make the sauce

  • In a medium saucepan, melt butter over medium heat, add onion and cook until softened, about 6 minutes.
  • Add flour, salt, pepper, and Italian seasoning and cook, stirring frequently, until mixture is pale golden for about 5 minutes.
  • Whisking constantly, pour in 2 cups of milk, cook for a few minutes and add the remaining 2 cups of milk, whisk until smooth. Cook mixture stirring constantly until it starts to boil.
  • Reduce heat to low and simmer gently, stirring occasionally, until the sauce thickens and is very creamy about 8 - 10 minutes. Taste and adjust for salt and pepper.
  • Remove from heat and stir in 1 1/2 cup of shredded cheese until melted.

Assemble and bake

  • Mix the potatoes with the béchamel sauce and transfer the mixture to the baking dish, top with the remaining 1 cup of mozzarella cheese and transfer the dish into the oven.
  • Bake for 1 hour or 1 hour and 10 minutes until the potatoes are tender.
  • Serve and enjoy!



Calories: 251kcal | Carbohydrates: 27g | Protein: 17g | Fat: 8g | Saturated Fat: 5g | Cholesterol: 30mg | Sodium: 505mg | Potassium: 781mg | Fiber: 4g | Sugar: 7g | Vitamin A: 610IU | Vitamin C: 16mg | Calcium: 501mg | Iron: 4.8mg
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Leave a reply


I love au gratin potatoes, even when they are from a box. I can't wait to have this version!


Amy H

I love Potato Gratin, but I have never made it myself. This recipe looks so good.


Tabitha Blue

I haven't had potatoes gratin in so long, and this recipe looks delicious!!! I'm never the best at thinking up of sides, this is a great one to save :)


Shannon Gurnee

We love making potatoes with our meals, but I've never tried making them by scratch. This looks like a delicious recipe!


Katrina Ellen

These potatoes look like they would be so amazing. I am definitely going to have to try these.


Adele Aiken

what type of potato is best for this recipe


Yukon potatoes are great!


Lisa Szymanski

You mention that you use a 9 x 9 pan but the recipe says 9 x 13. Which is it?


you can use any size you prefer. I usually use 9 by 13 to feed the family. For a smaller portion, go with 9 by 9.


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