Ingredients:

  • 2 ½ cups (320 g) All-Purpose Flour, plus extra for dusting
  • 1 teaspoon (5 g) Fine Sea Salt (for crust)
  • 1 cup (225 g / 2 sticks) Unsalted Butter, cut into ½-inch cubes and deeply chilled
  • ½ cup (120 ml) Ice Water
  • 1 tablespoon (15 ml) Apple Cider Vinegar or Vodka (optional)
  • 3 cups (450 g) Fresh Blueberries (or frozen, unthawed)
  • 3 cups (450 g) Fresh Blackberries (or frozen, unthawed)
  • ¾ cup (150 g) Granulated Sugar
  • ¼ cup (4 tablespoons / 30 g) Tapioca Starch or Cornstarch
  • 1 teaspoon (5 ml) Pure Vanilla Extract
  • 1 tablespoon (15 ml) Fresh Lemon Juice
  • Pinch of Salt (for filling)
  • 1 large Egg Yolk
  • 1 tablespoon (15 ml) Heavy Cream or Milk
  • 1 tablespoon (15 g) Demerara Sugar or Coarse Sugar (for sprinkling)

Instructions:

  1. Prepare the Pastry: Whisk together flour and salt in a large bowl. Using a pastry blender, two knives, or a food processor, cut the chilled butter into the flour until the mixture resembles coarse crumbs with some pea-sized chunks remaining. Do not overmix; those chunks are key for flakiness.
  2. Add Liquid and Chill Dough: Gradually drizzle in the ice water and cider vinegar, mixing just until the dough comes together. Divide the dough in half. Flatten each half into a thick disc, wrap tightly, and chill in the refrigerator for a minimum of 60 minutes.
  3. Prepare the Filling: Gently place blueberries and blackberries in a large bowl. In a separate small bowl, whisk together the sugar, starch (tapioca or cornstarch), and pinch of salt. Sprinkle this mixture over the berries. Add the vanilla extract and lemon juice. Gently fold the ingredients together until the berries are coated.
  4. Roll and Assemble: On a lightly floured surface, roll one disc of chilled dough into a 12-inch circle. Carefully transfer the dough to the 9-inch pie plate, trimming the edges. Spoon the berry mixture evenly into the bottom crust. Roll the second disc of dough and cut it into strips for a lattice top, or place it whole and cut vent holes. Trim, fold the top and bottom crusts together, and crimp the edges securely.
  5. Initial Chill and Preheat: Place the assembled pie in the freezer for 15 minutes. This is crucial for stabilizing the crust fat. Preheat the oven to 425°F (220°C).
  6. Bake: Whisk the egg yolk and cream for the egg wash. Brush the entire crust with the egg wash and sprinkle generously with demerara sugar. Bake at 425°F (220°C) for 15 minutes.
  7. Reduce Heat and Finish: Reduce the oven temperature to 375°F (190°C) and continue baking for another 50–60 minutes, or until the crust is deeply golden brown and the filling is bubbling thickly in the centre. (If edges brown too quickly, cover them loosely with foil.)
  8. Cool Completely: Transfer the baked pie to a wire rack and allow it to cool completely for at least 3–4 hours before slicing. The filling must set fully to avoid running.