Spinach and Feta Pie

Serve the spinach and feta pie as a lean main course with a salad, or cut into small squares for a light holiday snack that everyone will love.
Preheat the oven to 350°F. Heat the oil in a skillet over medium-high heat. Cook the onion, stirring frequently, until softened, 3-5 minutes. Transfer to a large bowl.Squeeze as much moisture out of the spinach as possible. Add to the bowl with the onion. Add the cheese, breadcrumbs, salt, pepper, nutmeg and eggs; mix well. (You can prepare it 2 days before this point. Cover and refrigerate.)Brush a 9-by-13-inch baking dish with butter. Roll out the phyllo on a clean countertop; cover with lightly dampened paper towels. Line the pan with 1 phyllo sheet, covering with the remaining batter. Lightly brush with butter. Top with another sheet; brush with oil again. Repeat with the butter and fillet to make a total of 6 sheets.Place the spinach mixture on a baking sheet. Place the phyllo on the edges of the filling. Trim the edges of the remaining phyllo sheets so that they fit inside the mold. Place 1 phyllo leaf on top of the filling and lightly brush with butter. Repeat with the remaining phyllo and butter. Bake until lightly browned and bubbling, about 45 minutes. Allow to cool for 15 minutes before serving.Prepare in advance: For freezing: Bake the pie as directed, allow to cool completely, wrap in foil and freeze. Before serving: Bake, covered with foil, at 375ºF for 20 minutes. Uncover and continue baking until fully warmed, another 10-20 minutes. (If the dough starts to brown too much, cover it again with foil.)