for the Crust
2 1/2 cups all purpose flour
1 tablespoon sugar
3/4 teaspoon salt
10 tablespoons (1 1/4 sticks) chilled unsalted butter, cut into 1/2-inch pieces
1/3 cup chilled solid vegetable shortening, diced
6 tablespoons (or more) ice water
for the Filling
1/2 cup granulated sugar
3 tablespoons cornstarch
2 tablespoons finely grated lemon zest
2 tablespoon. fresh lemon juice
Pinch table salt
4 cups fresh blueberries, stemmed, rinsed, and dried
Blend flour, sugar and salt in processor. Add butter and shortening and cut in using on/off turns until mixture resembles coarse meal. Add 6 tablespoons ice water and process until moist clumps form, adding more water by teaspoonfuls if dough is dry. Gather into ball; divide into 2 pieces. Flatten each into disk. Wrap each in plastic; chill 2 hours.
Position rack in lowest third of oven and preheat to 400F. Mix together sugar, corn starch, lemon juice and lemon zest in a medium bowl. Add blueberries and toss to blend.
Roll out 1 dough disk on floured surface to 12-inch round or a 5 x 13 inch rectangle. Transfer to 9-inch-diameter glass pie dish or a 4 x 12 inch tart pan. Fold edge under, forming high-standing rim; crimp. Add filling. Roll out second dough disk on floured surface. Using a star-shaped cookie cutter, cut out stars and place over top of pie filling. Place in oven and bake pie 20 minutes. Reduce oven temperature to 375F. Continue baking until juices bubble thickly and crust is deep golden, covering edges with foil if browning too quickly, about 1 hour. Let pie cool 1 hour before cutting.