# List of Ingredients:
→ Potatoes
01 - 2.5 lbs 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
# How to Make It:
01 - Preheat oven to 375°F. Grease a 9x13-inch baking dish generously with unsalted butter.
02 - In a medium saucepan, combine heavy cream, whole milk, minced garlic, Kosher salt, black pepper, and nutmeg. Warm over medium-low heat until just steaming, without boiling. Stir in half of the thyme.
03 - Arrange half the potato slices in an even layer within the prepared baking dish.
04 - Pour half the warm cream mixture over the potatoes. Sprinkle with half of the Gruyere and half of the Parmesan cheese.
05 - Place remaining potato slices on top. Pour over the remaining cream mixture, and finish with the remaining Gruyere, Parmesan, and thyme. Dot the surface with unsalted butter.
06 - Cover the dish tightly with foil and bake for 45 minutes.
07 - Remove the foil and bake an additional 25 to 30 minutes, until the potatoes are tender and the surface is golden and bubbling.
08 - Allow the gratin to rest for at least 15 minutes before portioning, to let the sauce thicken.
