In a large mixing bowl, combine flour and salt. Using a pastry blender, cut in 1/2 cup shortening, and continue blending until the crumbs are the size of large peas. Add the remaining shortening, and continue to blend and cut in until it resembles coarse meal. Sprinkle water over the flour mixture, and toss lightly with a fork. Gather the dough into a ball, and divide into two.
Roll out one disk and place in the bottom of a 9-in 23 cm pie plate. Mix together the sugar, corn starch, cinnamon and lemon zest. Sprinkle a few tablespoons of this mixture over the bottom crust, then spoon in half the berries. Sprinkle half the remaining sugar mixture, then the remaining berries. Top with the remaining sugar. Drizzle with lemon juice, and dot with butter.
Roll out the pastry for the top crust and lay it on top. Pinch the edges together and cut vents for the steam in the top crust.
Preheat Broil King Keg or Broil King pellet grill to 375°F (191°C), use the diffuser kit. Bake for 90 minutes, or until golden brown, juices at the vent should be bubbling. Let cool for an hour before serving.
