Add cherries, sugar, salt, cinnamon, cornflour and vanilla to a medium saucepan. Cook on medium-low for 10 minutes, stirring occasionally.
Once all the sugar and cornflour is dissolved, increase to a medium heat for another 5-10 minutes. The filling should get very thick. Begin to stir constantly, making sure it doesn't burn.
Take off the heat and add the kirsch, giving it a good stir.
Let Cool
Filling Pie
Preheat your oven to 220°Celsius
Prepare your pie dish by rolling out one portion of pie dough.
Fill the pie dish with the cooled cherry filling, and pop in the fridge.
While the pie is in the fridge you can roll out your second portion of pie dough, and either do a lattice like I have, using cutters to make shapes or do a full top crust.
Take the pie out of the fridge and arrange the top as you like, then pop it back in the fridge for 10 minutes.
Put the pie dish on a baking sheet lined with foil. Beat 1 egg and a bit of water in a small bowl, and brush the top of the pie with the egg wash. Sprinkle a bit of raw sugar on top.
Put it in the oven to bake for 20 minutes.
Turn down the oven to 175°Celsius and cook for a further 40 minutes. Pie should be golden brown and you should see the juices bubbling.
Let the pie rest for about 4 hours, if you cut too soon the filling will be runny
Notes
You'll need the recipe of a double crust pie to do this or use a store-bought pie dough