Sweet Buttery Crust:

1. In the bowl of a food processor, combine pastry flour, sugar, salt, and butter. Pulse until the mixture is crumbly. Add the ice water one tablespoon at a time, pulsing between each addition until the dough comes together.
2. Turn the dough out onto a floured surface and shape into a disk. Wrap in clingfilm or wax paper and refrigerate for at least an hour.

Blueberry Basil Filling:

1. In a large bowl, combine all ingredients except the egg and raw sugar. Toss the blueberries together and set aside.
2. Preheat oven to 350 degrees F.
3. On a well floured surface, roll out dough into a 15x12-inch rectangle. Using a knife or pizza cutter, cut out into rectangles (you should get 6-8).
4. Brush edges of rectangles with beaten egg then spoon some blueberries in the center of each rectangle. Fold the dough over, and pinch the edges with a fork to seal.
5. Place the pies on a parchment-lined baking sheet, gently pierce each pie with a knife, brush with the egg, and sprinkle with raw sugar.
6. Bake for 30-35 minutes, until the juices have run from the pies and the pastry shells are golden.
7. Transfer to a wire rack and let cool.
8. Combine the ingredients for the icing in a small bowl and whisk until thick and smooth. If you need more milk, add ½ teaspoon more at a time. Drizzle the icing over each pie before serving.