In a bowl, combine flour and salt; cut in shortening until crumbly. Sprinkle with water; toss until mixture is moist enough to shape into a ball. On a floured surface, roll out pastry to fit a 9-in. pie pan. Flute edges. Combine filling ingredients; spoon into the crust. Bake at 400° for 25 minutes. For topping, combine flour and brown sugar; cut in butter until crumbly. Sprinkle over filling. bake 40 minutes longer. Cover edges with foil during the last 15 minutes to prevent overbrowning if necessary.