# Ingredient list:
→ Potatoes
01 - 2 1/2 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 grated Gruyere cheese
05 - 1/2 cup grated Parmesan cheese
06 - 2 tablespoons unsalted butter, plus extra for greasing
→ Aromatics & Seasonings
07 - 2 cloves garlic, minced
08 - 1 1/2 teaspoons Kosher salt
09 - 1/2 teaspoon freshly ground black pepper
10 - 1/4 teaspoon ground nutmeg
11 - 1 tablespoon fresh thyme leaves or 1 teaspoon dried thyme
# Step-by-step guide:
01 - Preheat the oven to 375°F. Coat a 9x13-inch baking dish generously with 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, without letting it boil. Stir in half the thyme.
03 - Arrange half of the sliced potatoes in an even layer in the prepared baking dish. Pour half of the heated cream mixture evenly over the potatoes.
04 - Sprinkle half of the Gruyere and half of the Parmesan cheese over the potatoes. Layer the remaining potato slices on top. Pour over the rest of the cream mixture. Top with the remaining Gruyere, Parmesan, and thyme. Dot with additional butter.
05 - Cover the baking dish tightly with foil and bake for 45 minutes.
06 - Remove the foil and continue baking for 25 to 30 minutes, until the potatoes are tender and the top is golden and bubbling.
07 - Let cool for at least 15 minutes before serving, allowing the sauce to thicken.
