In medium bowl, stir together 2 cups flour, 1/2 cup quick cooking oats, and 1 teaspoon salt. Using pastry blender, cut in 2/3 cup shortening until pieces are pea-size.
Sprinkle 1 tablespoon water over part of mixture; gently toss with fork. Push moistened dough to side of bowl. Repeat, using 1 tablespoon water at a time, until all dough is moistened. (You will need 8 to 10 tablespoons total water.)
Divide in half; form each half into a ball. On lightly floured surface, flatten 1 dough ball. Roll from center to edge into 12-inch circle. To transfer pastry, wrap around rolling pin; unroll into a 9-inch pie plate, being careful not to stretch pastry. Trim pastry even with rim of pie plate. Fill pie plate with filling.
On lightly floured surface roll remaining dough into 14-inch circle; cut slits for stream to escape. Place on top of fruit filling; trim to 1/2 inch beyond edge of pie plate. Fold top crust under bottom crust; crimp edge.
Makes pastry for 2-crust pie, or two 1-crust pies.