Directions

1. In a large bowl combine flour, sugar and salt. Use a pastry cutter to cut in cold butter until you have a coarse, crumbly pea size mixture. (Alternatively, pulse in a food processor)
2. In a bowl mix sour cream, ice water and vinegar. Add sour cream mixture to the dough a tablespoon at a time. Finish mixing with hands to until it just comes together.
3. Form into 2 discs, one slightly larger than the other. Seal well and chill for at least an hour.
4. Pre-heat oven to 425°F/220°C with rack positioned in the centre.
5. Working one disc of dough at a time, remove dough from refrigerator 10 minutes before rolling. On a generously floured surface, roll out the larger disc of dough to 1/8” thickness and 2” larger than the pie dish.
6. Transfer and fit into the pie dish leaving 1” overhang. Refrigerate for 15 minutes.
7. Prepare the blueberry filling by sprinkling the blueberries with sugar, corn starch, lemon juice and cinnamon and toss to combine.
8. Fill the chilled pie shell with the blueberry mixture and dot with cubes of butter. Refrigerate while preparing the remaining dough.
9. Roll out the second disc of dough to 1/8” thickness and 14” square. Cut twelve- ¾ ” strips.
10. Lay six strips horizontally, evenly spaced and parallel to one another over the filled pie.
11. Fold back every second strip of dough and place a strip of dough vertically over the remaining strips of dough and filling. Place back the horizontal strips of dough over top the vertical strip of dough. Repeat by alternating with the other strips of dough.
12. Trim and fold the edges of the dough around edge of pie. Brush with the egg wash. Sprinkle with coarse sugar.
13. Bake in the the pre-heated oven for 20 minutes at 425°F/220°C, then reduce temperature to 350°F/176°C and bake for another 45-50 minutes until bubbling and golden brown.
14. Allow to rest at room temperature for at least 2 hours before serving. Serve with ice cream.