To create the pie crust, combine the flour, sugar, salt, and plant butter in a bowl.
Note: Make sure the butter is VERY COLD, otherwise your pie crust will become mushy and unworkable. I recommend cutting the butter into small cubes and placing it in the freezer for 30 minutes before adding it to the recipe.
To the crust, start adding 1 tablespoon of ice water at a time, until you can squeeze the dough just enough for it to barely stick together. I added a total of 5 tablespoon of ice water to mine, but yours may differ.
Once you have formed a ball of dough, divide it into two, cover in plastic wrap, and refrigerate for at least 30 minutes to give it time to chill.
While the dough is chilling, wash the cherries. Then remove the stems and pits, and slice each cherry in half.
Tip: You can use frozen pitted cherries for this if you want to skip all of that work!
Add the sliced cherries to a large pan over medium heat. Add the sugar, lemon juice, vanilla, and plant butter to the cherries. Use a masher to gently smush the cherries so they can release even more of their juices. Cook for 5-7 minutes, until they start to soften.
Then add the cornstarch and quickly whisk it into the mixture, breaking up any clumps. Remove from heat.
Remove one half of the pie crust from the fridge and very generously flour a clean surface and your rolling pin. Roll the dough out into a circle and place it in a gently greased pie dish. Transfer the pie filling to the pie crust.
Take the second half of the pie crust out of the fridge and roll it out into a long rectangle. Use a pizza cutter to cut eight 1-inch strips. Place 4 strips vertically. Then create a lattice with the other 4 going the other way.
Whisk up the vegan egg wash ingredients and use a pastry brush to brush all over the pie crust. Dust the crust with coarse sugar (optional).
Bake the pie at 400F for 20 minutes, then reduce the heat to 350F and bake for another 30 minutes.
Keep an eye on your pie and if the crust starts to burn, cover the pie with a layer of foil to keep it from burning!
Remove the pie from the oven, give it plety of time to cool off, then slice and enjoy!