Ingredients

  • 1 1/2 cups creme fraiche
  • 1/3 cup whipping cream
  • 3 pounds Yukon Gold potatoes, peeled, cut into 1/8-inch-thick slices
  • 1 1/2 teaspoons coarse kosher salt
  • 3/4 teaspoon ground black pepper
  • 1 1/2 teaspoons dried thyme

Method

  • Place rack in center of oven and preheat to 400°F. Generously butter 13x9x2-inch glass or ceramic baking dish. Whisk creme fraiche and whipping cream in medium bowl to blend.
  • Arrange 1/3 of potato slices in bottom of prepared baking dish, overlapping slightly. Sprinkle with 1/2 teaspoon salt, 1/4 teaspoon pepper, and 1/2 teaspoon thyme. Drop 1/3 of creme fraiche mixture (about generous 1/2 cup) in dollops over potatoes, then spread evenly over (layer will be very thin). Repeat layering 2 more times.
  • Bake gratin 30 minutes. Reduce oven temperature to 350°F and continue to bake until potatoes are tender and top is golden brown, about 25 minutes longer. Let gratin rest 20 minutes before serving. DO AHEAD