In a large bowl whisk together salt, flour, sugar and baking powder, make a well in the centre and add the egg, egg yolk and butter (cubed), mix together (you can also use a food processor, pulse until dough just starts to come together), move the dough to a flat surface and knead gently until the dough comes together and is soft, wrap in plastic and refrigerate for 30 minutes.
FOR THE FILLING
In a small to medium pot combine 2 cups of blueberries, sugar, flour, salt and cinnamon, bring to a boil over medium heat, cook stirring for approximately 2 minutes until thickened, remove from heat and stir in lemon juice and remaining 1/2 cup of blueberries, let cool.
Remove the dough from the fridge, divide it in half, one piece wrap again in plastic and refrigerate, the other piece roll to approximately 1/8 inch thickness place the dough in a lightly greased and floured 8-9 inch (20-22cm) pie pan, trim the dough to fit the pan.
Prick bottom of crust with a fork, top with the cooled blueberry filling. Remove the remaining dough from the fridge, roll on floured surface in 1/8 inch thick and cut into strips.
Place the strips on top in a criss cross fashion. While the oven is pre-heating, cover the pie with plastic and chill for approximately 15-20 minutes. Chilling the pie will help with solidifying the fat, which helps prevent shrinkage.
Pre-heat oven to 350F (180C).
Brush top lightly with milk and bake in pre heated oven for approximately 25-30 minutes or until golden. Let cool completely before serving.
Notes
If you have a with the dough sticking to the board, then just add the pieces to the pie plate and fit them in using your fingers, just try to get it as even as possible. It happens to me all the time, because our house is very warm in the summer.I have enjoyed this another way also, you could cut back to 1 1/2 cups of berries and 2 tablespoons of sugar. But before adding the filling, spread the bottom of the dough with blueberry jam. It’s more of a classic thinner crostata. Delicious this way too!If you find the pie browning too much before it is baked, then cover with foil and continue baking.The completely cooled crostata should be covered and stored in the fridge. It will keep for up to 4-5 days in the fridge.Let the pie cool completely, then wrap well in foil and place in a freezer bag. Label it and freeze for up to 4 months. To serve it, thaw at room temperature. It can also be heated in a low oven until warmed through.