In a mixing bowl stir together the 2 cups flour and the salt. Cut in shortening or lard until pieces are the size of small peas.
Sprinkle 1 tablespoon of the water over part of the mixture; gently toss with a fork. Push to side of bowl. Repeat until all is moistened. Divide dough in half. Form each half of dough into a ball.
On a lightly floured surface, flatten each ball of dough with you hands. Roll out one portion of dough from center to edges, forming a circle about 12 inches in diameter. Wrap pastry around a rolling pin. Unroll pastry into a 9-inch pie plate. Ease pastry into pie plate, being careful not to stretch pastry. Trim pastry even with rim of pie plate.
For top crust, repeat rolling remaining dough. Cut slits to allow steam to escape. Cover with plastic wrap until needed.
In a large mixing bowl combine the sugar, the 1/4 cup flour, and lemon peel. Add fresh or frozen blackberries; toss gently until coated. (If using frozen blackberries, before adding let them stand 15 to 30 minutes or until the berries are partially thawed but still icy.)
Transfer berry mixture to the pastry-lined 9-inch pie plate. Adjust top crust. Trim, seal, and flute edge. To prevent overbrowning, cover edge of pie with foil.
Bake in a 375 degree oven for 25 minutes for fresh berries (50 minutes for frozen berries). Remove foil. Bake for 20 to 25 minutes more for fresh berries (20 to 30 minutes for frozen berries) or until top is golden and center is bubbly.
Meanwhile, in a small saucepan combine packed brown sugar and half-and-half or light cream. Cook and stir over low heat until sugar melts. Stir in chopped toasted hazelnuts. Pour over hot pie. Cool. Makes 8 servings.