3 pounds Yukon Gold or Russet potatoes, peeled and sliced into 1/8 inch rounds
1/4 cup unsalted butter
1/4 cup all purpose flour
2 1/2 cups whole milk
2 cups sharp cheddar cheese, shredded
1 cup Monterey Jack or Gruyere cheese, shredded
1 teaspoon salt
1/2 teaspoon black pepper
1/2 teaspoon garlic powder
1/2 teaspoon onion powder
1/4 teaspoon ground nutmeg
Fresh parsley for garnish
Instructions
Preheat your oven to 375 degrees Fahrenheit and grease a 9 by 13 inch baking dish with butter or cooking spray. Carefully peel your potatoes and slice them into thin, even rounds about one eighth of an inch thick. Using a mandoline slicer is highly recommended to ensure the slices cook at the same rate throughout the dish.
In a medium saucepan over medium heat, melt the butter until it begins to foam. Whisk in the flour and cook for about one to two minutes, stirring constantly to remove the raw flour taste without browning it. This creates the base that will thicken your creamy cheese sauce.
Slowly pour in the milk while whisking vigorously to prevent any lumps from forming. Continue to cook and stir until the mixture thickens and begins to bubble slightly. Stir in the salt, black pepper, garlic powder, onion powder, and nutmeg to season the base thoroughly.
Remove the saucepan from the heat and stir in one and a half cups of the shredded cheddar and all of the Monterey Jack cheese. Stir until the cheese is completely melted and the sauce is smooth and glossy. Taste the sauce and adjust the salt or pepper if necessary to suit your preference.
Arrange half of the potato slices in an even layer in the prepared baking dish. Pour half of the cheese sauce over the potatoes, spreading it to the edges. Repeat with the remaining potatoes and the rest of the sauce. Cover the dish tightly with aluminum foil to trap the steam and help the potatoes soften.
Place the dish in the oven and bake for 45 minutes. Remove the foil and sprinkle the remaining half cup of cheddar cheese over the top. Return the dish to the oven, uncovered, and bake for another 20 to 25 minutes until the potatoes are tender when pierced with a fork and the top is bubbly and golden brown. Let the dish rest for 10 minutes before serving to allow the sauce to set.
