Directions

1. In a large bowl combine the flour, sugar and salt. Use a pastry cutter to cut in the cold butter until you have a coarse, crumbly pea-size mixture. Alternatively, pulse in a food processor.
2. Sprinkle the vinegar and ice water into mixture a tablespoon at a time. Finish mixing dough with hands to until it just comes together; do not over mix.
3. Form into two discs, wrap well in plastic wrap and chill for at least an hour.
4. Pre-heat oven to 400°F /205°C with rack positioned in the centre. Line a large baking sheet (or two small) with parchment paper.
5. Mix the blueberries (do not thaw if using frozen), sugar, flour, lemon and cinnamon together in a separate bowl. Cube 2 tbsp of cold butter and set aside.
6. Prepare the egg wash by whisking the egg and milk.
7. Remove dough from refrigerator 15 minutes before rolling. Roll out the dough on a floured surface into a rough circle measuring about 1/8” thick and 12” in diameter. 
8. Transfer dough to the lined baking sheet, fill each with blueberry mixture leaving 3” around the edge and dot with cubes of butter.
9. Fold and overlap the edges of the dough, leaving a 4” opening in the middle.
10. Brush the dough with egg wash.
11. Scatter the sliced almonds on the dough and lightly press in.
12. Bake in the middle rack of the pre-heated oven for 40-55 minutes until bubbling and golden brown.
13. Allow to rest at room temperature. Serve with ice cream.