To save a little time, cut the potatoes with a mandoline. Or try the slicing disk on your food processor; press lightly on the plunger to create thin slices.


Credit: Photography by Christopher Testani

Recipe Summary test

1 hr 40 mins


Ingredient Checklist


Instructions Checklist
  • Preheat the oven to 400°. In a large skillet, melt the butter over medium heat. Add the leeks. Cook, stirring often, until softened, 4 to 5 minutes. Stir in the cream and sage. Bring to a gentle boil. Add 1 cup cheese and stir until melted, a minute or two. Stir in 2 tsp. salt and 1 tsp. pepper. Remove from heat. Add the potatoes and stir to evenly coat the slices. Transfer to a 9-by-13-inch baking dish, spreading the potatoes in an even layer. Top with the remaining 1 cup cheese.

  • Cover the dish with foil. Bake for 30 minutes. Uncover the gratin and bake until the top is golden brown in spots and the potatoes are tender when pierced with a knife, 25 to 30 minutes more. Let the gratin rest for 15 minutes before serving.