Kale and Butternut Squash Pie

Preparation:

Put oven rack in middle position and preheat oven to 425°F. Heat 2 tablespoons oil in a 12-inch heavy skillet over moderately high heat until hot but not smoking, then sauté squash with 1/4 teaspoon salt and 1/4 teaspoon pepper, stirring frequently, until browned and just beginning to soften, about 5 minutes. Transfer to a plate and spread in 1 layer to cool.
Add remaining tablespoon oil to skillet and reduce heat to moderate, then cook onion, garlic, sage, and remaining 1/2 teaspoon salt and 1/4 teaspoon pepper, stirring frequently, until onion is softened, about 7 minutes. Stir in kale and water and cook, covered, stirring occasionally, until kale is just tender, about 6 minutes. (Skillet will be full, but volume will reduce as vegetables steam.) Cool, uncovered, to room temperature.
Brush pie pan with some butter. Unroll puff pastry and fit one layer of pastry into bottom of the pan and cut to fit. Spread half of kale mixture in pastry shell. Gently stir together squash and cheese in a bowl and spread evenly over kale. Top with remaining kale.
Spread remaining puff pastry sheet over the pie filling, pressing the pastry sheets together at the pie pan’s edges. Brush top with butter and bake until deep golden brown, 20 to 25 minutes. Cool pie in pan on a rack 5 minutes. Cut into wedges and serve hot!