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.

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 varied the thickness of my strips for this one. Place on a baking sheet lined with parchment paper. Place in the fridge until you are ready to use.
4. To make the rhubarb filling, cut the rhubarb and place into a large bowl. Add the vanilla and mix to combine.
5. In a small bowl, combine the tapioca starch and sugar, and mix to combine to ensure there are no lumps. Add to the rhubarb and mix well until the rhubarb is fully coated in the sugar mixture. There will be some dry ingredients that don't stick to the rhubarb - just make sure they are as evenly dispersed as you can. 
6. Transfer the filling to the prepared bottom crust and settle it in as much as you can so that it sits flat.
7. Remove the pan with the lattice strips from the fridge and lattice the pie as desired. If you run out of strips you can trim any overhanging, press together, re roll and chill for 5-10 minutes and cut yourself some more.
8. 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.
9. Place the finished pie 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.
10. When you are ready to bake the pie, 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 pie 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.
11. Remove the baked pie 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.
12. Store leftovers lightly covered at room temperature.