# What You'll Need:
→ Potatoes
01 - 2.5 pounds Yukon Gold or Russet potatoes, peeled and sliced 1/8-inch thick
→ Dairy
02 - 2 cups heavy cream
03 - 1 cup whole milk
04 - 2 cups Gruyere cheese, grated
05 - 1/2 cup Parmesan cheese, grated
06 - 2 tablespoons unsalted butter, plus extra for greasing
→ Aromatics & Seasonings
07 - 2 cloves garlic, minced
08 - 1/2 teaspoon freshly ground black pepper
09 - 1 1/2 teaspoons Kosher salt
10 - 1/4 teaspoon ground nutmeg
11 - 1 tablespoon fresh thyme leaves or 1 teaspoon dried thyme
# Method:
01 - Set oven to 375°F. Generously grease a 9x13-inch baking dish with butter.
02 - Combine heavy cream, whole milk, minced garlic, Kosher salt, pepper, and nutmeg in a medium saucepan. Warm gently over medium-low heat until steaming, avoiding boiling. Stir in half the thyme.
03 - Arrange half of the potato slices in a single layer across the bottom of the prepared baking dish.
04 - Pour half of the warm cream mixture over the potatoes. Evenly sprinkle half the Gruyere and Parmesan.
05 - Place the remaining sliced potatoes in an even layer. Pour in the rest of the cream mixture. Top with the remaining Gruyere, Parmesan, and thyme. Dot the surface with unsalted butter.
06 - Cover the dish tightly with foil. Bake for 45 minutes.
07 - Remove foil. Continue baking for an additional 25-30 minutes, until potatoes are tender and the top is golden and bubbling.
08 - Allow the gratin to rest at least 15 minutes after baking for the sauce to set before serving.
