Start by making the pie dough. In a food processor, add the flour, sugar, and salt, and mix until combined.
Add cold cubed butter and blend until the butter and the flour mixture are combined.
Add ice water and mix for 10 seconds. Press the dough between your fingertips and if the dough comes together, it’s ready. If not, add another tablespoon of water.
Transfer the dough to a clean floured surface and gather the dough into a ball. Cover with plastic wrap and place in the fridge for at least an hour.
Pit the cherries and transfer them into a bowl and add sugar, lemon zest, lemon juice, vanilla extract, and flour. Mix with a spoon until well combined and there are no pockets of flour visible.
Remove the dough disk from the fridge and let it warm up a little bit for a few minutes at room temperature.
Transfer the pie dough disk onto a clean floured surface and roll with a rolling pin into a circle.
Transfer the cherry filling to the center of the rolled dough and fold the edges into pleats.
Mix an egg with a teaspoon of milk or water and brush the dough with the egg wash. Top the egg wash with coarse sugar or any sugar for a sweet and crispy exterior.
Transfer the galette to a parchment paper-lined baking sheet and bake in a 200c (400f) preheated oven for 25-30 minutes, or until the filling is bubbling and the crust is golden brown.
Slice the warm galette and serve with vanilla ice cream!