6ouncessharp cheddar cheeseshredded (about 1 ½ cups)
1ounceParmesan cheeseshredded (about ¼ cup)
Instructions
Place a rack in the center of your oven and preheat to 375°F. Coat a 9x13-inch casserole dish with nonstick spray and set aside.
In a medium pot or wide skillet with high sides, heat the butter over medium-low heat. Add the onion. Cook for 8 to 10 minutes, stirring often, until translucent. Stir in the garlic and cook just until fragrant, about 1 minute more. Turn off the heat.
Stir in the milk, 1 teaspoon of the salt, and the pepper. Set aside to cool.
Peel the potatoes. With a mandoline or very sharp chef's knife, slice the potatoes into VERY thin slices, about ⅛ to ¼-inch thick (thinner is better). Place potatoes in a large bowl. Sprinkle with the flour and remaining 1 teaspoon salt. With your hands, toss to coat the potatoes as evenly as possible.
Spread one-third of the sliced potatoes evenly in the bottom of the prepared dish. Spoon 1 cup of the milk mixture over the top. Sprinkle with ½ cup shredded cheddar cheese. Repeat two more times so you have a total of 3 layers each of potato, the milk mixture, and the cheddar cheese, ending with the cheese on top.
Lightly mist a large sheet of aluminum foil with nonstick spray. Cover the dish with foil spray-side down. Bake the scalloped potatoes for 35 minutes, then uncover and bake for an 25 additional minutes, until the potatoes are tender when pierced with a fork.
Remove the dish from the oven and sprinkle with the Parmesan cheese. Turn the oven to broil and return the pan to the oven for 1 to 3 minutes, until the cheese is golden brown and bubbly. Don’t walk away and let them burn!
Allow the potatoes to stand at room temperature for 20 to 25 minutes prior to serving to allow the milk mixture to set and thicken (don’t worry, they
Notes
*I do not recommend russet potatoes for this recipe, as they have less flavor, a dryer texture, and thicker skin than Yukon golds.
TO MAKE AHEAD: The dish can be prepared through Step 3 one day in advance (wait to add the milk/cheese until just before you bake). Store covered in the refrigerator, let come to room temperature, then continue with the recipe as directed.
TO STORE: Place cooked and cooled leftovers in an airtight storage container in the refrigerator for up to 4 days.
TO REHEAT: Gently reheat leftovers in an oven-safe baking dish in the oven at 350°F until warmed through, adding a splash of broth as needed. You can also reheat this dish in the microwave until hot.
TO FREEZE: I do not recommend freezing scalloped potatoes as they can become mealy.