Pre-heat oven to 375 degrees.
In a medium bowl, combine cherries, sugar and cornstarch. Set aside.
Stretch (or roll if you made your own) your pie crust on lightly floured parchment paper.
Place cherries in the center of the crust. Make sure to leave about 2 inches boarder around the outside to fold over.
Fold the crust edges up and over the cherries (I tucked as I circles the fruit).
Transfer the parchment to a baking sheet.
Brush dough with egg wash and sprinkle evenly with sugar.
Bake for 45-55 minutes, until the fruit center is bubbly.
Allow galette to rest at least 15 minutes before slicing.