Position knife blade in processor bowl. Add flour, shortening, baking powder, and salt; cover. Process 5 seconds or until mixture resembles coarse meal.
With processor running, add ice water in a steady stream through food chute until dough forms a ball. Process dough an additional 2 minutes.
Roll dough out onto a lightly floured surface to 1/4-inch thickness. Cut with a 1 1/2-inch biscuit cutter. (Cut efficiently, for leftover dough should not be rerolled.) Prick tops of biscuits with the tines of a fork.
Place on ungreased baking sheets. Bake at 400° for 20 minutes or until biscuits are lightly browned.