- FOR THE PASTRY: Sift together the flour and confectioners' sugar. Make a well in the center and add the margarine. Mix with fingertips until the mixture resembles coarse breadcrumbs. Mix in the cold water, working quickly to form a mass. Push the mixture with the heel of your hand to thoroughly combine. Roll into a ball, cover with plastic wrap and refrigerate for 1 hour.
- Preheat oven to 425ºF. Roll out the pastry to line the bottom of a 9" springform pan, reserving leftover pieces to make cut-outs for the top of the pie. Refrigerate for 30 minutes. Cover with parchment or waxed paper and baking weights (dried beans or rice). Bake for 10 minutes.
- FOR THE FILLING: Whisk together the egg whites and brown sugar in bowl. Add the syrup and mix until smooth. Stir in the evaporated milk, pumpkin puree, rum, vanilla, spices and salt. Combine thoroughly. Pour into the pre-baked pastry shell. Bake 15 minutes, then reduce heat to 350ºF and bake for 1 1/2 hours, or until a knife inserted in center comes out clean.
- FOR THE CUT-OUTS: Cut leaves or other decorative shapes from the leftover pastry. Place on cookie sheet, brush with egg wash and bake for approximately six minutes or until golden. Place pastry shapes on cooled pie.