Apple, Leek, and Butternut Squash Gratin | Whole Living Eat Well - Whole Living

Ingredients

• 3 tablespoons extra-virgin olive oil
• 2 medium leeks, white part only, trimmed of roots and tough outer leaves, thinly sliced crosswise, well washed and dried
• Coarse salt and ground pepper
• 1/2 cup dry sherry
• 1 tablespoon chopped fresh sage, plus leaves for garnish
• 1 pound butternut squash, peeled, seeded, and sliced 1/8-inch thick
• 1 pound apples, such as Gala, Cortland, Baldwin, or Macoun, peeled, halved, cored, and cut into 1/8-inch thick slices
• 1/2 cup freshly grated Parmesan cheese