Sift together flour, salt, sugar & baking powder into a bowl. Cut shortening into flour mixture with pastry cutter (or two knives) until mixture resembles cornmeal. Stir in 1/4 C of the cold water, the add remaining 1/4 C cold water until combined. Cover dough & allow it to rest in refrigerato for 30 minutes.
Divide dough in half. Place on lightly floured board & pat out. Using rolling pin, roll out 1 piece of dough the size of a 9" pie plate. Put crust in pan & trim off excess dough around the edge. Roll out second ball of dough for pie crust top.
FOR THE FILLING:
Preheat oven to 425 degrees F.
Mix sugar, tapioca, zest, cinnamon, nutmeg & raisins in a large bowl. Lay tomato slices in pie crust. Sprinkle mixture over tomatoes. (Overlapping will occur, but tomatoes will shrink in size when baked). Gently lay top pie crust over filling, tucking in the extra crust around the edges. Pinch dough with fingers or fork to seal edges. Using a knife, make 4 - 6 slits in top of crust to allow steam to escape. Brush top with egg white & sprinkle with a little sugar to give your crust a shine.
Place pie in oven & bake for 25 minutes. Reduce temperature to 350 degrees F. & continue to bake for 20 more minutes. Cool on wire rack. Enjoy!