Whisk together flour, confectioners' sugar, and salt in a large bowl. Using two table knives or your fingertips, work butter and shortening into the dry ingredients until mixture resembles coarse meal. Add pecans, if using, and toss with a fork to incorporate. Add water 1 tbsp. at a time, drizzling it around edge of bowl. Stir with fork until moist clumps form. (Overworking dough will toughen it.) With lightly floured hands, shape dough into a disk, then score pastry with the side of your hand to relax the gluten. Cover with plastic wrap and refrigerate for 1 hour.
Preheat oven to 425°. Butter a 9" ovenproof glass pie plate. Roll out dough on a lightly floured surface into a 12" round. Loosely wrap dough around a floured rolling pin, then unroll dough onto pie plate and press gently into the creases. Do not stretch dough. Trim excess dough, leaving a 1⁄4"–1" overhang. Fold edge over and form a double thickness. Seal edges with a floured fork. Prick with a fork at 3⁄4"–1" intervals. Chill pastry for 30 minutes. Butter a piece of aluminum foil and place foil, buttered side down, onto crust. Press foil completely flush against crust's sides and scatter dried beans across surface.
Position shelf in lower third of oven. Bake crust for 15–18 minutes or until sides begin to brown. Remove crust from oven. After 30 seconds, gently remove foil and beans. Reduce oven temperature to 375°. Return crust to oven and continue baking until golden brown, 3–5 minutes. If it puffs up, tap it gently with a fork to let air out. Allow to cool before filling.