Preheat oven to 350°.
To prepare crust, lightly spoon 1 cup flour into a dry measuring cup, and level with a knife. Combine 1/4 cup flour, ice water, and lemon juice, stirring with a whisk until well blended to form a slurry. Combine remaining 3/4 cup flour, powdered sugar, and 1/4 teaspoon salt in a large bowl; cut in shortening with a pastry blender or 2 knives until mixture resembles coarse meal. Add slurry; toss with a fork until flour mixture is moist.
Gently press mixture into a 4-inch circle on 2 sheets of overlapping heavy-duty plastic wrap; cover with 2 additional sheets of overlapping plastic wrap. Roll dough, still covered, into a 12-inch circle. Freeze dough 10 minutes or until plastic wrap can easily be removed.
Remove dough from freezer. Remove top 2 sheets of plastic wrap; let the dough stand 1 minute or until pliable. Fit dough, plastic wrap side up, into a 9-inch pie plate, allowing dough to extend over edge. Remove remaining plastic wrap. Press dough into bottom and up sides of pie plate. Fold edges under; flute. Bake at 350° for 8 minutes. Cool on a wire rack.
To prepare filling, place syrup and next 5 ingredients (through egg white) in a large bowl; beat with a mixer at medium speed until well blended. Stir in pecans and vanilla. Pour filling into prepared crust. Bake at 350° for 50 minutes or until edges puff and center is set (shield edges of piecrust with foil if crust gets too brown). Cool on a wire rack.
To prepare the topping, combine the whipped topping and bourbon until blended. Serve with pie.