Combine flour, sugar, baking powder, and salt; cut in shortening with a pastry blender until mixture resembles coarse meal. Combine egg yolk and water to equal 1 cup. Add liquid to flour mixture; stir with a fork until dry ingredients are moistened. Shape dough into a ball; chill. Use as directed in desired recipe.
Note: This recipe may be used to prepare a 10-inch deep-dish bottom crust pastry with a lattice top.