Preheat your oven to 200°C/400°F.
In a large mixing bowl, combine the pitted cherries, sugar, cornflour, lemon juice, vanilla extract, and cinnamon. Mix thoroughly.
Roll out one sheet of shortcrust pastry and use it to line a 9-inch pie dish.
Pour the cherry mixture into the pastry-lined dish.
Roll out the second sheet of pastry and use it to cover the top of the pie. Crimp the edges of the pastry together to seal the pie.
Use a sharp knife to make a few small slits in the top of the pastry to allow steam to escape.
Brush the beaten egg over the top of the pastry.
Bake the pie in the preheated oven for 40-45 minutes, or until the pastry is golden brown and the filling is bubbly.
Once baked, remove the pie from the oven and let it cool for a few minutes before serving. Enjoy your delicious cherry pie!