For Filling: In 4-quart saucepan, combine water, chicken, carrots, celery and onion. Bring to a boil. Reduce to a simmer and cook for 10 minutes, stirring occasionally. Add chicken bouillon, pepper and butter. Dissolve cornstarch and flour into whipping cream and stir into chicken mixture. Simmer for 3 minutes, stirring frequently until thickened. Add peas and set aside. For Crust: Heat oven to 400 degrees F. Combine flour and salt. Using pastry blender, cut in shortening until particles the size of small peas form. Sprinkle one tablespoon of water at a time over flour mixture and toss with fork to blend. Add enough water to hold the dough together. Form into 2 balls. Roll out bottom crust on floured surface to 1 inch larger than inverted 9-inch deep-dish pie plate. Lift dough off floured surface by rolling onto rolling pin and unroll over pie plate. Ease the dough into the plate loosely and press in place. Trim bottom crust even with edge of plate. To Assemble: Pour filling into bottom crust. Roll out top crust and cut slits for steam to escape. Cover filling with top crust and fold top crust under bottom crust. Seal crust and flute edge. Bake in a 400 degrees F oven for 35 to 40 minutes or until the crust is golden brown and filling is bubbling. Let stand for 15 to 20 minutes before serving.