This Potato Gratin is the perfect addition to any meal, whether its weeknight dinners or holiday occasions. For this Au Gratin style side dish, thin slices of Yukon gold potato are baked in cream, milk, two cheeses, garlic, and thyme, until bubbling and golden brown.

Potato Gratin - In Casserole Dish with Spoon

I understand the love for mashed potatoes, but this Potato Gratin is what you’ll always find on my Thanksgiving table instead. It’s so much better! And for the record, I do think mashed potatoes are wonderful, but you can’t beat the creamy, cheesy, textured goodness that is potatoes au gratin.

Why This Recipe Is The Best

✅ Tried and true – I ate a tremendous amount of potato gratin in my childhood. My mom went to culinary school in France, and she made the best potato gratin ever on the regular. This tastes just like my mom’s, with a rich flavor and heavenly texture.

✅ Perfect texture – We will cook the potatoes covered, then later uncovered, to get the potatoes tender in the layers, and also perfectly browned on top.

✅ Rich flavor – We’ll use a mix of cream and milk to give rich flavor without getting too heavy, plus two kinds of cheese, gruyere for flavor and a melty texture, and parmigiano reggiano for sweet sharpness. Garlic and fresh thyme round out the dish.

✅ Leftover friendly – This dish keeps beautifully, and unless you have a large number of people to feed, gives an ample amount of leftovers for future meals. Feel free to double the batch and make two trays.

There are so many dishes that you can serve with potatoes au gratin, like Slow Cooker Short Ribs, Parmesan Crusted Chicken, and Pork Tenderloin. I’ll share more suggestions below, but it goes well with basically any meat entree.

Gratin - In Green Casserole Dish with Thyme

What Type of Potato To Use

I recommend using Yukon Gold here, which has a wonderfully tender flesh and delicious flavor. Other good options would be Russets or Idaho potatoes. Try to stay away from waxy potatoes like new potatoes or red bliss.

How to Make It Step by Step:

As a general overview, we’ll need to:

  1. Slice the potatoes.
  2. Toss them with milk, cream, cheese, garlic, thyme, salt, and pepper.
  3. Bake.

Set up the cream and milk first to prevent browning and capture starch

Place the cream and milk together in a big mixing bowl before you start slicing the potatoes, then put the potatoes directly into the milk and cream as you slice them. This does two things:

#1. It prevents the potatoes from turning brown and oxidizing.

#2. It lets us capture the precious starch from the potato slices and puts it into the milk and cream, thickening the liquid.

A lot of potato gratin recipes solely use cream for the baking liquid, but retaining the starch allows us to replace some of that cream with milk. This cuts down slightly on the richness without making the liquid thin.

It’s a common default to soak potatoes in water to prevent browning, like for Crispy Hash Browns, so I like to set up the dairy bowl first to make sure I don’t accidentally forget.

Sliced Potato Rounds in Bowl with Cream

Slicing Recommendations

Even though you can slice the potatoes by hand, I highly suggest using a mandolin or a food processor for slicing.

When cutting by hand, the slices will be uneven and it’s very tedious.

If you get a good quality mandolin, it’s not as scary to use as you might think, and I use mine ALL the time.

Add the Cheese

When the potatoes are sliced up, add two kinds of cheese.

My choices are sharp and tangy aged parmigiano reggiano and melty, nutty aged gruyere.

Both cheeses serve different purposes and are equally necessary. I recommend getting both, and know that often times grocery stores will cut larger pieces of cheese into any size you need, so long as you ask.

Potatoes Au Gratin Ingredients in Bowl with Cheeses and Potato Rounds

Add garlic, thyme, salt, and pepper

Add your flavorings of choice directly to the bowl. My favorite flavor combination is tons of fresh thyme leaves, garlic, salt, and pepper:

Fresh Thyme Leaves, Seasoning, and Cheeses with Potato Rounds

I find 2 tsp of salt is perfect for me using a coarse kosher salt. Use less if you cook with table salt.

I think thyme is the best herb for potato gratin because it has a wonderful flavor, and a texture that isn’t disruptive. While you can do rosemary, the leaves are a lot bigger and more noticeable, so try to chop it up well if you go that route.

Toss the ingredients well to evenly coat the potatoes, then dump the entire contents of the bowl into an 8×12 baking dish.

Cover Tightly and Bake

Cover the dish tightly with aluminum foil, then place the entire baking dish on a sheet pan.

Trust me, don’t skip the sheet pan, or you’ll have a burned mess on the bottom of the oven. Since the liquid has cream in it, it loves to boil over and seep out the sides.

Casserole Dish Covered with Foil on Sheet Pan

Bake the au gratin potatoes for an hour, then remove the foil. It will look like this:

Potatoes Au Gratin - Partially Baked in Casserole Dish

The potatoes will be mostly tender, but now it’s time to bake for 30 more minutes to really brown the top and let the liquid reduce down:

Au Gratin Potatoes Recipe Baked in Green Dish with Caramelized Dairy on Sides of Pan

That’s better.

Your glorious homemade potato gratin should now be very tender in the middle but cheesy and brown on the surface. Enjoy!

Recipe Pairing Ideas That Go Well:

Recipe FAQ and Tips

How do you store leftover Potato Gratin?

Keep in an airtight container in the fridge for up to 5 days.

Can you freeze potato gratin?

Technically yes, in an airtight container in the freezer for up to 2 months, but the texture is noticeably worse. The potatoes get a bit mealy, and the cream curdles.

How do you reheat potato gratin?

You can either microwave it until hot and bubbling, or re-warm in a 350F oven for about 10 minutes, until hot and bubbling.

Can you make Au Gratin Potatoes ahead of time?

The only success I’ve had with making it ahead is if you can truly keep all the potato slices submerged in the cream and milk liquid to prevent browning, then you can make it the night before. You can do this by putting the potato slices, cream, and milk in a Ziploc bag and squeezing all the air out.  There are some scattered ideas on the internet about parbaking the potato gratin, but accompanying reports of it not going well.

Did you enjoy the recipe? Please leave a 5-star rating in the recipe card below and/or a review in the comments section further down the page.

Potato Gratin In Casserole Dish with Spoon and Thyme

Potato Gratin

Servings: 8
Prep Time: 15 mins
Cook Time: 1 hr 30 mins
Total Time: 1 hr 45 mins
This Potato Gratin is the perfect simple side dish for any type of meal, whether its weeknight dinners or holiday meals. Thin slices of Yukon gold potato are baked in cream, milk, two cheeses, garlic, and thyme, until bubbling and golden brown.
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Ingredients

  • 1 cup heavy cream
  • 1 cup milk
  • 3 lbs yukon gold potatoes
  • 1/4 lb gruyere cheese grated
  • 1/4 lb parmigiano reggiano cheese grated
  • 3 cloves garlic pressed or minced
  • 10 sprigs fresh thyme
  • 2 tsp salt
  • black pepper

Instructions 

  • Preheat the oven to 400 degrees F.
  • In a large bowl, combine the heavy cream and milk.
  • Using a mandolin, slice the potatoes very thinly (if you don’t have a mandolin, you can use a knife, but it will be a lot more work and time). As you finish slicing each potato, place it into the cream milk mixture so the slices don’t brown.
  • When the potatoes are all sliced, add the gruyere and parmigiano cheeses to the bowl, along with the garlic, the leaves from the thyme sprigs, salt, and a few cracks of black pepper. Toss well.
  • Pour the potatoes and cream into an 8×11 baking dish, then cover the dish tightly with aluminum foil.
  • Place the baking dish on a sheet pan, then bake for 1 hour.
  • Remove the foil and bake for 30 minutes more, until the potatoes are tender, bubbling, and golden brown on top. Serve and enjoy!

Notes

Reheating: You can either microwave it until hot and bubbling, or re-warm in a 350F oven for about 10 minutes, until hot and bubbling.
Storing: Keep in an airtight container in the fridge for up to 5 days.
Freezing: Technically you can freeze leftovers in an airtight container for up to 2 months, but know that the texture will be worse. The potatoes will get a bit mealy and the cream will curdle.

Nutrition

Calories: 376kcal, Carbohydrates: 34g, Protein: 13g, Fat: 22g, Saturated Fat: 13g, Cholesterol: 74mg, Sodium: 615mg, Fiber: 4g, Sugar: 4g

Nutrition is estimated using a food database and is only intended to be used as a guideline for informational purposes.

Course: Side Dish
Cuisine: American
Author: Joanne Ozug