Measure 4 tablespoons water into a measuring cup and set aside.
Place shortening, flour, and salt in food processor.
Cover and process using quick pulses until mixture is crumbly.
With food processor running, pour water in all at once through feed tube until dough leaves the side of the bowl. (It will not form a ball. Just combined enough to come away from the sides.
Remove from food processor and shape into two equal balls. Then shape into flattened rounds.
Place one round on lightly floured service, flatten with a rolling pin. Roll into 9X13 rectangle and transfer to baking dish.
Place second round on lightly floured service, flatten with a rolling pin and cut into strips for lattice top.