Combine the flour and a pinch of salt in a mixing bowl, then add cold butter pieces. Use a pastry cutter or your fingers to work the butter into the flour until the mixture resembles coarse crumbs. Gradually add ice water, one tablespoon at a time, mixing until the dough just comes together.
Shape the dough into two disks, wrap each in plastic wrap, and refrigerate for at least 30 minutes. This helps relax the gluten and keeps the crust flaky.
While the dough chills, prepare the cherry filling by combining pitted cherries, sugar, cornstarch, and lemon juice in a bowl. Stir gently until the cherries are coated and the mixture begins to thicken; set aside.
Preheat your oven to 375°F (190°C). Remove one dough disk from the fridge and roll it out on a lightly floured surface into a 12-inch circle. Transfer it carefully to a pie dish, pressing gently to fit and trimming any excess.
Pour the prepared cherry filling into the crust, spreading it evenly. Dot the filling with small knobs of butter if desired, for extra richness.
Roll out the second dough disk into a similar circle and place it over the filling. Trim excess dough and crimp the edges to seal the pie. Cut a few small slits on top to allow steam to escape.
Mix the beaten egg with water to make an egg wash, then brush it over the crust for a shiny, golden finish. This step adds a beautiful sheen after baking.
Bake the pie in the preheated oven for about 50 minutes, or until the crust is golden brown and the filling is bubbling through the slits. If the edges brown too quickly, cover them with foil or a pie shield.
Allow the pie to cool for at least 2 hours before slicing. This helps the filling set and prevents runny slices, making each piece easy to serve with a perfect, juicy center and crisp crust.
