Ingredients

  • 2 tablespoons unsalted butter
  • 3 pounds butternut squashpeeled, seeded and cut into cubes
  • 1 cup water
  • 1 garlic clove, minced
  • 1 cup creme fraiche
  • Salt and freshly ground pepper
  • 6 large egg yolks
  • 1 cup shredded Gruyere cheese

Method

  • Preheat the oven to 350.
  • Butter a deep 2-quart baking dish.
  • Melt the butter in a large skillet.
  • Add the squash and stir to coat.
  • Add the water, cover and cook over moderate heat until the squash is tender, about 10 minutes.
  • Uncover and cook over high heat until the water has evaporated, about 3 minutes.
  • Transfer the squash to a large bowl, mash it and let cool to room temperature.
  • Add the garlic and creme fraiche to the squash and season with salt and pepper, then whisk in the egg yolks.
  • Spread the squash in the prepared baking dish and scatter the cheese over the top.
  • Cover the squash with foil and bake for about 40 minutes, or until almost set.
  • Increase the oven temperature to 425.
  • Uncover the squash and bake in the upper third of the oven for about 12 minutes, or until the cheese is browned.
  • Remove the gratin from the oven and let stand for 10 minutes before serving.