1 - To make the pastry, place the flour and salt in a large bowl.
2 - Mix well.
3 - Add the cubes of butter and shortening and mix them in (I like to use my hands to mix the fat into the flour, but you can use a pastry blender) just until it looks like coarse oatmeal with some pea-sized bits remaining.
4 - Place the egg in a 2-cup measure and beat it with a fork.
5 - Beat in the vinegar and just enough ice-cold water to bring it to the 1-cup mark.
6 - Stir this into the flour mixture, just until the dough clings together.
7 - I like to use my hands for this part as well, but a wooden spoon would also work.
8 - Try not to overmix it.
9 - On a lightly floured surface, gather the dough into a ball and divide it into 5 evenly sized portions.
10 - Shape each portion into a disc and wrap tightly in plastic.
11 - Chill 2 of these discs for 1 hour.
12 - Freeze the other 3 in a resealable freezer bag for future use.
13 - The pastry keeps well in the freezer for up to 2 months.
14 - Preheat the oven to 350°F.
15 - Place the rack in the lower third of the oven.
16 - Line a baking sheet with aluminum foil to catch drippings.
17 - On a lightly floured surface, roll out 1 disc of pastry into a 12-inch circle, or thereabouts.
18 - Place it in the bottom of a 9-inch pie plate, with the pastry overhanging the edges of the pie plate.
19 - To make the filling, place the saskatoon berries in a large bowl and stir in the 1/2 cup sugar and the cornstarch until well combined.
20 - Pour the berry mixture into the bottom of the pie.
21 - Dot with the butter.
22 - On a lightly floured surface, roll out the pastry in another 12-inch circle for the top crust.
23 - Use a ruler to guide you when cutting the pastry into 6 wide, long strips to keep the edges straight.
24 - Save the 2 end pieces in case you need to do any patching.
25 - I like wide strips, but if you like a thinner look, feel free to cut thin strips of pastry.
26 - Weave the pastry strips, going over and under, making sure they connect with the edges of the pie crust.
27 - Fold over the edges of the bottom crust, tucking in the lattice ends.
28 - This will help to trap the juices and give a rustic look.
29 - If you prefer a cleaner, tidier look, you can trim the overhanging pieces and crimp the edges with a fork.
30 - Brush the top of the pie with the egg wash.
31 - Sprinkle with the remaining Tbsp sugar.
32 - Place the pie on the prepared baking sheet and bake it for about 90 – 100 minutes, until it’s golden brown and bubbling.
33 - Remove the pie from the oven and place it on a wire rack to cool.
34 - Serve the pie warm or at room temperature with whipped cream or ice cream.
35 - Makes 6 servings.
36 - This keeps well if covered with plastic and refrigerated for up to 4 days.
