3 lbs Yukon Gold potatoes, peeled and sliced 1/8 inch thick
1/4 cup unsalted butter
1/4 cup all-purpose flour
2 cups whole milk
1 cup heavy cream
3 cups sharp cheddar 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
1 tablespoon fresh thyme, chopped
Instructions
Preheat your oven to 375 degrees Fahrenheit. Grease a 9×13 inch baking dish generously with butter or a light coating of oil to ensure the potatoes do not stick to the edges during the long baking process.
In a medium saucepan over medium heat, melt the butter. Once melted, whisk in the flour and cook for about one to two minutes until the mixture is bubbling and lightly golden, which removes the raw flour taste.
Slowly pour in the milk and heavy cream while whisking constantly to prevent lumps. Continue to cook and stir until the sauce thickens. Remove from heat and stir in two cups of the shredded cheddar cheese, salt, pepper, garlic powder, onion powder, and nutmeg until the cheese is completely melted and the sauce is smooth.
Arrange half of the sliced potatoes 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. Sprinkle the remaining one cup of cheese and the fresh thyme over the top.
Cover the dish tightly with aluminum foil and bake for 45 minutes. Remove the foil and continue baking for another 25 to 30 minutes, or until the potatoes are fork-tender and the top is bubbly and golden brown. Let the dish rest for 10 minutes before serving to allow the sauce to set.
