These delicious Cheesy Au Gratin Potatoes are easy to make and perfect with dinner. They are great for the holidays or even just a weeknight dinner. The thinly sliced potatoes are combined with a 3 cheese sauce that's creamy and delicious. It is the ultimate comfort food.
Spray a 9x13 baking dish with avocado oil spray and set aside.
Add the butter to a saucepan over medium heat.
Once the butter has melted, add the flour and whisk until it's smooth and makes a roux.
Slowly begin adding the milk, whisking continuously to keep it smooth. Be sure to whisk out any clumps.
Turn off the heat and add in the cheddar cheese, garlic powder, salt, and pepper.
Whisk until it's smooth and creamy.
Place a layer of sliced potatoes across the bottom of the prepared baking dish. You'll want to use 1/3 of the potatoes. They can overlap slightly, but try not to have them directly stacked on each other so that the cheese can get on all of the potatoes.
Pour 1/3 of the cheese sauce over the top of the potatoes and spread it evenly.
Top the cheese layer with another single layer of potatoes.
Top that layer of potatoes with another 1/3 of the cheese sauce.
Add the final layer of potatoes and pour the remaining cheese sauce on top, spreading evenly.
Top with the gruyere and parmesan.
Cover the baking dish tightly with foil and bake for 30 minutes.
Remove the foil and bake for an additional 20-30 minutes. Just until the potatoes are cooked through and the top begins to become golden brown.
Enjoy!
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Notes
Pre-shredded cheese has an anti-caking agent on it so it will not give as smooth of a texture as freshly grated cheese. You can test if the potatoes are done by piercing the center with a fork. It should slide in easily.
Alternating layers of potatoes and cheese sauce will make sure that all of the potatoes are coated in cheese sauce and you aren't left with plain potatoes. That's why it's important to make sure they aren't directly stacked on top of each other before pouring the cheese on top.
It's important to evenly slice your potatoes. I like to use a mandolin for this (be careful if you do!). This will make sure that the entire dish cooks evenly.
Taste your cheese sauce! Some people like a little extra salt in there.