In a small bowl, combine 1-1/2 cups flour, sugar and salt; cut in shortening until crumbly. In another bowl, whisk water and remaining flour until smooth. Gradually add to crumb mixture, tossing with a fork until dough forms a ball. Divide pastry in half. Roll out each portion between two pieces of plastic wrap into an 11-in. circle. Freeze for 10 minutes.
Remove one sheet of plastic wrap from one pastry; transfer to a 9-in. pie plate coated with cooking spray. Remove remaining
plastic wrap. Trim pastry to 1/2 in. beyond edge of pie plate; flute edges. Repeat with remaining pastry.
In a large bowl, beat the egg substitute, egg, sugars, salt and spices until blended. Beat in pumpkin. Gradually beat in milk. Pour into crusts. Bake at 375° for 50-60 minutes or until a knife inserted in the center comes out clean. Garnish with whipped topping.