Spanakopita (greek Spinach Pie)

Shred spinach and mix with scallions, parsley, dill, and salt. Let stand 10 minutes. Squeeze out moisture by the handful. Heat olive oil in a large skillet and saute onions until transparent, about 5 minutes. Stir in spinach and cheeses. Remove from heat and cool, stirring occasionally, to room temperature. Beat eggs in with a wooden spoon. Brush bottom and sides of a 13x9x2-inch baking dish with melted butter. Line the dish with a sheet of filo, pressing the edges of pastry firmly into the corners, and against the sides of the dish. Brush surface of filo with melted butter, spreading it all the way to the outside edges and lay another sheet of filo on top. Repeat until you have used 7 layers of filo in all. Spread spinach mixture evenly over last layer of filo and smooth it into the corners. Place another sheet of filo on top, brush with butter and repeat, layering with remaining filo. Turn edges over to form a crust. Brush the top with the remaining butter. Bake at 300 degrees for 1 hour or until the pastry is crisp and delicately browned. Cut into squares and serve hot.