Step by step

1. Make the dough: Fit the Stand Mixer with the pastry beater. Add the flour, sugar and salt into the work bowl and turn the mixer to speed 1 for 10 seconds. While the mixer stirs, add in the cold butter, then increase to speed 2 for one minute. Turn back to stir and then slowly drizzle in ice water. Remove the work bowl from the mixer and use your hands to gather the dough into two smooth discs. Wrap the discs in plastic wrap and chill/rest the dough for at least an hour in the refrigerator.

2. When dough is ready, set the oven rack to the bottom third and preheat the oven to 200°C. Place them in a large bowl. In a separate bowl, mix together the cornstarch, sugar, and grated orange zest. Set aside.

3. Lightly flour the countertop and roll one disc into a circle about 0.5 cm thick; fit the dough into the pie plate and trim the edge of the dough leaving a 2.5 cm overhang (for crimping after you create the lattice). Roll out the second disc into the same sized circle, then cut the circle into 2.5 cm strips.

4. Make the filling: Place the blueberries into a big bowl, add the sugar mixture and stir to coat evenly, then pour the blueberries into the pie plate. Dot the top of the blueberries with butter. Weave the strips into a lattice top, then trim the edges of the strips and fold the strips and bottom crust edge under. Then, press the edge of the crust with a fork to seal. Brush the top of the pastry with the egg wash.

5. Place a sheet of tin foil on the rack below your baking rack to catch any juices that bubble out while baking. Place a foil shield over the pie and bake the pie for 30 minutes. Then, reduce temperature to 175°C and bake until the crust is browned and juices are clearly bubbling through the lattice (about 25-30 minutes longer). Remove the pie shield for the last 10 minutes of baking.