Mix the dry ingredients thoroughly to combine the baking powder with the flour. Add the oil and water. Mix until a dough forms. Try not to knead it while forming it into a large ball. If the dough is too dry, add water a tablespoon at a time. Separate the dough into two equal balls for easier rolling; each portion will yield a single 9-inch pie crust or one dozen small tart shells. Roll the dough out right away and press into pie plate. You're ready to add your filling and bake your pie!