In a large mixing bowl stir together the sugar and flour. Stir in rhubarb, raspberries, and apple. Transfer to a pastry-lined 9-inch pie plate. Trim pastry even with the rim of the pie plate. Cut slits in the top crust. Place top crust over fruit filling. Seal and flute the edge. Cover edges with foil; bake in a 375 degree F. oven for 25 minutes. Remove foil. Bake 20 to 25 minutes more or until top is golden and fruit is tender. Cool on a wire rack for two hours before serving. Makes 8 servings.
Pastry for a Double-Crust Pie
In a bowl stir together flour and salt. Using a pastry blender, cut in shortening until pieces are pea size. Sprinkle 1 tablespoon cold water over part of the mixture; gently toss with a fork. Push moistened dough to side of bowl. Repeat using 1 tablespoon cold water at a time until all the dough is moistened (6 to 7 tablespoons total). Divide dough in half. Form each half into a ball. On a lightly floured surface, flatten 1 dough ball. Roll from center to edges into a 12-inch circle. To transfer pastry, wrap it around the rolling pin; unroll into a 9-inch pie plate. Ease pastry into pie plate, being careful not to stretch pastry. Fill as above. roll remaining dough into a circle about 12 inches in diameter. Continue as above.