Potatoes Au Gratin

Potatoes Au Gratin are a one of my favorite side dishes. I actually grew up eating the boxed version (GASP!) but it wasn’t until recently that I started making these myself and there’s just no comparison!

This recipe for Potatoes Au Gratin is a keeper for sure. The potatoes are so creamy on the inside and the top of the dish gets a crusty browned cheese that everyone will fight over!

We, like most people, serve mashed potatoes every year for Thanksgiving. But I think this year I might serve these instead (or maybe both!). It’s always nice to try something new and these are definitely something that I know our family will love!

So here’s what you need to make potatoes au gratin:

• 3 pounds of red potatoes
• 1 and 1/4 cup of grated Gruyère cheese
• 1 and 1/4 cup of grated parmesan cheese
• 1 small yellow onion
• 2 cups heavy cream (sorry…milk won’t work for this one)
• 2 teaspoons salt
• 1 teaspoon of pepper
• 1 teaspoon of garlic powder
• 1 tablespoon of fresh thyme leaves

Just from looking at the ingredient list, you can already tell that these are some really decadent potatoes! They are a special treat and they don’t skimp on flavor. I don’t make too many things with heavy cream but potatoes au gratin is just one of those things that needs to be nice and creamy. Trust me, it’s worth it!

What type of potatoes should you use for potatoes au gratin?

I like to use these red skinned potatoes because they hold up to all the cheese sauce and don’t become mushy. If you use a russet potato, the dish can tend to turn to mush. The skin on the red potato is also very tender and I like the fact that I don’t need to peel them!

The potatoes in this dish are sliced very thin. I used this Oxo mandolin slicer that comes in a set of graters and slicers. I love it because it has everything all in one neat box that doesn’t take up a lot of space. Also, I’m quite fond of keeping my fingertips and this slicer comes with a finger guard. If you don’t use a guard, PLEASE be careful. A mandolin slicer is one of the most dangerous kitchen tools. If you don’t have one or don’t feel comfortable using one, just use a knife and take your time.

Once you’ve done your prep work, you can toss everything in together with the cheeses, cream, and seasonings. I like to use my hands to do this just so I can separate the potatoes as I toss them so they aren’t all stuck together.

After everything is combined, the potato mixture gets added to the greased baking dish and topped with more cheese! Cover it and bake it for 60 minutes, then uncover for 30 more minutes. The top should be a gorgeous golden brown!

Tips for making potatoes au gratin:

• Be careful slicing the potatoes! Use either a mandolin slicer WITH a finger guard, or a sharp knife.
• Use your hands to toss the potatoes in the cream so you can separate the potatoes that have stuck together.
• Use butter to grease your pan for extra color around the edges.
• Use THIS OXO slicer to grate your cheese, slice your potatoes, and even grate the onion!
• If the top doesn’t brown as much as you’d like, set the oven to broil and watch carefully for just a few minutes.

Print Recipe

5 from 6 votes

Potatoes Au Gratin

Prep Time15 mins

Cook Time1 hr 30 mins

Resting time15 mins

Total Time1 hr 45 mins

Course: Side Dish

Cuisine: American

Author: Coco and Ash

Ingredients

• 3 pounds red potatoes
• 1 and 1/4 cup grated gruyere cheese
• 1 and 1/4 cup grated parmesan cheese
• 1 small yellow onion (about 1/3 cup diced)
• 2 cups heavy cream
• 2 teaspoons salt
• 1 teaspoon black pepper
• 1 teaspoon garlic powder
• 1 tablespoon fresh thyme leaves

Instructions

• Pre-heat your oven to 400 degrees.
• Slice your potatoes as thin as you can. I use this mandolin slicer but you can use a knife and cut them to about 1/8 inch thick. 
• Mix your cheeses together and set aside 1/2 cup of cheese for the topping. 
• In a large bowl, whisk together the remaining 2 cups of cheese, onion, cream, salt, pepper, garlic powder and thyme.
• Add the potatoes to the mixture and toss to combine. The best tool for this is just your hands!
• Grease a 9x13 baking dish with either butter or cooking spray and add in the potato mixture. 
• Top the potatoes with the remaining 1/2 cup of cheese and cover the dish tightly with foil.
• Bake for 1 hour then uncover the potatoes and bake for another 30 minutes or until the top is browned. 
• Let the potatoes rest for 15 minutes before serving.