Preheat your oven to 375°F (190°C).
In a mixing bowl, combine flour and salt. Cut in the cold butter until the mixture resembles coarse crumbs.
Gradually add ice water, mixing until the dough comes together. Divide the dough in half, shape into disks, wrap in plastic, and refrigerate for at least 30 minutes.
Roll out one disk of dough on a floured surface and fit it into a 9-inch pie dish. Trim the edges.
In another bowl, mix huckleberries, sugar, cornstarch, lemon juice, and lemon zest. Pour the mixture into the pie crust and dot with butter.
Roll out the second disk of dough and place it over the filling. Trim and crimp the edges to seal. Cut a few slits in the top crust to allow steam to escape.
Bake for 50-60 minutes, or until the crust is golden brown and the filling is bubbly. Let cool before serving.