Cheesy Potatoes au Gratin (VIDEO)

Cheesy Potatoes au gratin cooking in a red casserole dish being scooped by a spatula.

5 from 5 votes

Cheesy Potatoes au Gratin (VIDEO)

These Cheesy Potatoes au Gratin are the perfect side dish for the holidays! The think layers of deliciously cheesy potatoes in a silky bechemel sauce are tender perfect with a holiday spread.

Prep Time30

Cook Time1

Total Time1 30

Course: Side Dish

Cuisine: American, French

Servings:

Author: Chris Joe

Equipment

Ingredients

4 lbs Yukon gold potatoes
4 tbsp unsalted butter plus more for greasing the baking dish
4 cloves garlic minced
1 tbsp fresh rosemary minced
1 tbsp fresh thyme minced
¼ cup all purpose flour
1 cup whole milk cold
2 cups heavy cream cold
1 tsp kosher salt
½ tsp black pepper
½ tsp freshly ground nutmeg
8 oz sharp cheddar cheese grated, 2 oz reserved for topping
8 oz gruyere grated, 2 oz reserved for topping

Instructions

Slice the potatoes into 1/16” thick rounds using a mandolin or knife. Place the potatoes in a large bowl.
In a large pot, heat unsalted butter over medium heat until melted. Add the garlic, chopped rosemary and thyme and saute for 30 seconds, then add the flour and whisk until combined and there are no lumps. Cook for 1 minute, then add the cold milk and whisk to remove any lumps, then add the heavy cream and whisk together. Season with salt and pepper.
Heat over medium heat until bubbling and slightly thickened, about 3-4 minutes. Grate in the nutmeg, then mix and turn off the heat. Fold in 6 oz of the cheddar cheese and 6 oz of the gruyere cheese until melted and let cool slightly. Pour the mixture over the potatoes and toss until fully coated.
Grease the baking dish with butter, then lay down the potatoes in flat, stacked layers until all the potatoes are layered.
Bake uncovered at 400°F for 45 minutes. Remove from the oven and top the potatoes with the reserved cheese. Return to the oven and bake for another 15 mintues or until the cheese is golden brown.
Let sit for 15 minutes to allow the potatoes to set and cool.

Video

Notes

Use a mandolin guard - I like using a mandolin because it ensures that the slices are even, which will help the dish cook evenly. HOWEVER - please use the guard that came with the mandolin or a cut resistant glove. Mandolins are very dangerous if used improperly. It's better to have uneven slices than to hurt yourself while making this dish!

Watch the heat when adding the cheese - Once the bechamel has cooled slighly off the heat, add the gruyere and sharp cheddar cheese a few handfuls at a time, mixing the cheese into the sauce and making sure it's smooth before adding more cheese. If the heat is too high, the cheese will become grainy, so watch this step carefully!

Use a shallow baking dish - I recommend using a wide shallow baking dish - this allows for more surface area, which will help the top layer of cheese turn crispy when broiled. This layer of cheese provides a nice textural contrast to the creaminess of the dish.

Let the potatoes rest before serving - The final step of letting the potatoes rest for 15 minutes is KEY to the success of this dish - once you've taken the potatoes out of the oven and set on a heatproof surface, leave them alone for 15 minutes! This will allow the potatoes to cool, thicken, and meld together. This makes a huge difference in the taste and texture of the final dish. If you do not let the potatoes rest before serving, they'll likely be too runny and too hot to enjoy. Do not skip resting!

Storage - Store any leftovers in an airtight container in the refrigerator for up to 3-4 days. I like to reheat it in the microwave but you can also reheat it in the oven at 325 for 20 minutes or until warmed through. If you have a large portion leftover, you may need to reheat for longer.

Make ahead - If you want to make this dish ahead of time, I would make the dish until step 4 (assemble the potatoes and bechamel sauce then layer in the baking dish) and then cover tightly with saran wrap or foil and store in the refrigerator until the day of (up to 3 days). When ready to cook, resume step 5 and bake!

Nutrition