PIE CRUST

1. Make Pie Crust as directed. I like to make my pie crust the night before or at least 2 hours before to give it time to rest.

BALSAMIC BLUEBERRY PIE FILLING

1. Place the berries, balsamic, vanilla and lemon zest in a medium pot. Cook down for 10 minutes over medium heat until the berries have released their juices and are starting to break down slightly and the mixture looks juicy. Combine the sugar and cornstarch in a small bowl. Sprinkle over the berries and stir to incorporate, then cook for a further 1-2 minutes over low heat until the mixture has thickened.
2. Transfer the mixture to an airtight container or a small sheet pan and place a piece of plastic wrap directly against the surface. Transfer to the fridge to cool completely.

ASSEMBLY AND BAKING

1. Unwrap the disc of pie dough and place onto a lightly floured surface. Roll the dough out, turning the dough 45˚ often as you are rolling to keep it even. You want the circle to be slightly larger than your pan. Transfer to a 9” loose bottomed tart pan,, and arrange to ensure that the dough is well settled. Leave the overhang settled over the edge of the pan. Place into the fridge while you roll out the second piece of crust for the lattice.
2. Take the rectangle of dough and roll out into a large rectangle approximately the same thickness as the base. The dimensions aren’t super important here but in order to maximise dough, keep one edge of it to just over 9” (so that you don’t have too many long strips hanging over the edge of your pie and wasting dough).
3. Using a pastry wheel and a ruler, cut strips of pie dough to your desired thickness. I made quite thick strips for this one. Place on a baking sheet lined with parchment paper. Place in the fridge until you are ready to use.
4. Transfer the chilled filling to the lined tart pan, smoothing to make sure it is nice and even.
5. Remove the pan with the lattice strips from the fridge and lattice the pie as desired. For this crostata I made a diagonal lattice. To set this up you lay a set of horizontal strips across the pie, then for the second set of strips, you place them at a 45 degree angle. (See video for explanation)
6. Once you have finished your lattice, carefully trim the outside edge so that is is flush with the side of the tart tin. To do this I usually just use the sharp edge of the tin and press against it to cut the pie dough cleanly (only do this if you have a tart tin with the sharper edges, otherwise you can fold excess under and crimp, or if you are using a pie pan, just trim the edges and press down to seal.
7. Place the finished crostata in the fridge to chill for at least 30 minutes. While it is chilling, preheat the oven to 425°f / 220°c, and arrange a baking rack in the bottom third and middle third of the oven.
8. When you are ready to bake the crostata, brush the top well with egg wash, and sprinkle with turbinado sugar. Place on a baking sheet and place on the lower rack, and bake for 20 minutes, until the pastry is turning golden brown and looks set. Then, reduce the oven temperature to 375°f / 190°c, move the baking sheet with the crostata on it to the middle rack, and bake for a further 40 to 50 minutes, until the pastry is deep golden brown and the filling is bubbling. Tent the top with foil at any time if you are worried it is browning too quickly. It is important you get a good bake on a fruit pie. If you don't you run the risk of a soggy bottom, so make sure it is very well baked.
9. Remove the baked crostata from the oven and allow to cool before removing from the pan and slicing with a sharp knife. Serve slightly warm or at room temperature. 

Store leftovers lightly wrapped at room temperature or in the fridge for up to 3 days.