In a food processor, pulse the flour, sugar, salt and cinnamon a few times to combine.
Add the cold diced butter and pulse the mixture until it resembles coarse meal (pea size pieces with bigger pieces of butter it’s ok). Mixture should be powdery and dry.
Add the ice cold water and pulse a few more times. The dough should stick together in between your fingers, if not add a tablespoon of water until it does.
Transfer the dough to a clean work surface and form 2 equal size pieces of dough. Wrap in plastic wrap and refrigerate for one hour until you are ready to use for your cherry pie.
Meanwhile prepare the cherry pie filling; in a saucepan, over medium heat add your pitted cherries, sugar, lemon juice, cornstarch and cinnamon and stir to combine.
Bring to a boil and cook for 8-10 minutes or until the mixture has thickened. If the mixture looks a bit dry, add a splash of water. Remove from the heat and allow to cool slightly. Set aside.
To make the cherry pie, preheat the oven to 350ºF. Remove the pie dough from the plastic wrap and on a clean surface dusted with flour roll the dough with a rolling pin. Roll the first piece of dough into a 13” circle and transfer to a 9” wide pie pan. The edges should hang a little over the edges of the pie dish.
Fill with the cherry pie filling, and add the cold butter cubes all over the filling.
Roll the second piece of dough into a 12” circle and use a pizza cutter or a knife to slice into ten 1 inch strips. Create a lattice crust over the top (see FAQ). Tuck in the excess dough at the edges.
In a small bowl, beat the egg with the milk or the melted butter and brush over the lattice crust and edges of the pie. Sprinkle the top with the coarse sugar. Bake for 40 minutes or until the cherry filling is bubbly and the crust is golden.