Preparation time: 10 minutes
Baking time: About 45 minutes

1. Line a 25 cm (10”) pie plate with pastry.
2. Bring 125 ml (1/2 cup) water and 125 ml (1/2 cup) sugar to a boil, stirring so that the sugar is well dissolved.
3. Whisk together the cornstarch with the remaining 125 ml (1/2 cup) cold water. Stir into the sugar syrup and cook until thickened. Remove from the heat.
4. Stir the remaining 185 ml (3/4 cup) sugar into the mixture, along with the salt, lemon juice and cinnamon (if using).
5. Fold in the blueberries and place into the pie shell. Cover with the top pastry crust, crimping the edges to seal well.
6. Brush the top with egg wash (made by beating 1 egg with 1 tbsp. water.) Cut a vent in the top crust with a sharp knife.
7. Bake in a preheated 200° C (400° F) oven for 10 minutes. Reduce the heat to 180° C (350° F) and continue baking until the pastry is cooked and lightly browned and the filling is bubbly, about 35 minutes.