Almost any mashed winter squash, including canned pumpkin, will work in this pie.
Preheat oven to 375°.
To prepare the crust, place the cookies in a food processor, and process until finely ground (to yield about 1 cup). Add the granulated sugar and butter, and pulse 8 times or until combined. Press crumb mixture into the bottom and up the sides of a 9-inch pie plate coated with cooking spray. Bake at 375° for 6 minutes; cool on a wire rack.
To prepare filling, place water and squash in a microwave-safe dish. Cover with wax paper; microwave at high 12 minutes or until very tender, stirring after 6 minutes. Drain and mash.
Combine the squash and the next 8 ingredients (squash through eggs) in a medium saucepan. Cook mixture over medium heat until thick (about 8 minutes), stirring constantly with a whisk. Pour the mixture into the prepared crust. Bake at 375° for 20 minutes or until set; cool pie on a wire rack. Top each serving with 1 tablespoon whipped topping.