Recipe Instructions:
1 1/2 cups whole milk
2 garlic cloves, divided
2 tablespoons unsalted butter, softened, divided
1 1/2 pounds Yukon Gold potatoes
Kosher salt and freshly ground pepper
2 cups grated Gruyère, divided
Heat the oven to 425°F. Pour the milk into a small heavy saucepan. Peel and smash 1 garlic clove and add to the milk. Warm over medium-low heat until the milk starts to bubble at the edges. Remove from the heat and let steep.
Peel the remaining garlic clove, cut in half, and rub the cut sides around the inside of an oval gratin dish about 9 inches long and 2 inches deep. Rub 1 tablespoon of the butter inside of the baking dish.
Peel the potatoes and cut into ⅛-inch-thick slices (I use a mandoline to get them nice and even), laying the slices on a kitchen towel to drain. Layer about one-third of the potatoes in the bottom of the baking dish, fanning them into concentric, overlapping circles. Season with salt and pepper; sprinkle with one-third of the cheese. Repeat with 2 more layers of potatoes, salt. pepper, and cheese, making the top layer as neat and tidy as you can.
Remove the garlic clove from the hot milk. Pour the milk evenly over the potatoes. Dot the top of the potatoes with the remaining 1 tablespoon of the butter. Bake the gratin for about 30 minutes, until browned and bubbly. Let cool for 5 minutes before serving.
