Instructions
To create the luscious pastry, begin by combining flour and salt in a large bowl, mixing thoroughly. Cut in the cold cubes of butter and vegetable shortening with your hands or a pastry blender until the mixture resembles coarse oatmeal with some pea-sized bits of fat still visible; this ensures the pastry will be flaky and tender. Next, beat the egg in a 2-cup measuring cup, adding vinegar and just enough ice-cold water to reach the 1-cup mark. Stir this liquid into the flour mixture gently with a wooden spoon or your hands, taking care not to overwork the dough to keep it light. Transfer the dough to a lightly floured surface, form it into a ball, and divide it into five equal discs. Wrap each tightly in plastic wrap; chill two discs for at least one hour before rolling, and freeze the remaining three for future pies—this dough stores beautifully for up to two months. Preheat your oven to 350°F and position the oven rack in the lower third. Line a baking sheet with aluminum foil to catch any juicy drips. On a lightly floured surface, roll one chilled dough disc into an approximate 12-inch circle. Gently place this into a 9-inch pie plate, letting the dough overhang the edges slightly. For the filling, toss the Saskatoon berries with sugar and cornstarch until fully coated, then spread them evenly over the bottom crust. Dot the filling with small pieces of butter to enrich the flavor. Roll out another disc into a similar 12-inch circle and, using a ruler for neatness, cut the pastry into six wide, long strips. Set aside the two end pieces for patching if needed. Weave the strips over and under each other to form a rustic lattice on top of the pie, ensuring the edges connect securely with the base crust. Fold the bottom crust edges over the lattice ends to seal the filling inside, trapping the delicious juices and creating a charming, rustic look. For a neater presentation, trim the excess dough from the edges and crimp using a fork. Brush the entire lattice top lightly with the beaten egg wash mixed with a tablespoon of water to achieve a beautiful golden glaze. Sprinkle the remaining tablespoon of sugar over the top for a sparkly finish. Place the pie on the prepared baking sheet and bake for approximately 90 to 100 minutes, or until the crust is golden brown and the filling is bubbling vigorously. Once baked, remove the pie from the oven and let it cool on a wire rack to allow the filling to set. Enjoy warm for the best flavor or at room temperature. This pie pairs wonderfully with fresh whipped cream or creamy vanilla ice cream. Leftovers can be covered tightly with plastic wrap and stored in the refrigerator for up to four days—though it rarely lasts that long! Tips: For even baking, rotate the pie halfway through the bake. If the crust browns too quickly, cover edges with foil to prevent burning.
