# What You Need:
→ 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
# Directions:
01 - Preheat oven to 375°F. Grease a 9x13-inch baking dish with unsalted butter.
02 - Combine heavy cream, whole milk, minced garlic, Kosher salt, black pepper, and nutmeg in a medium saucepan. Warm gently over medium-low heat until just steaming, avoiding boiling. Incorporate half of the thyme.
03 - Arrange half of the potato slices evenly in the prepared baking dish.
04 - Pour half of the infused cream mixture over the potato layer. Disperse half of the Gruyere and Parmesan cheese over top.
05 - Create a second layer with the remaining potato slices. Pour the rest of the cream sauce on top. Sprinkle with remaining Gruyere, Parmesan, and thyme. Finish with dots of unsalted butter.
06 - Cover the baking dish tightly with foil. Bake for 45 minutes.
07 - Remove the foil and continue baking for 25 to 30 minutes until potatoes are tender and the surface is golden and bubbling.
08 - Allow the gratin to rest for at least 15 minutes before serving. This ensures the sauce thickens and flavors meld.