Preheat to 375F. Line your aluminum baking sheet with a silicone baking mat.
In a bowl, mix together the sour cherries, honey, arrowroot powder, vanilla extract, and lemon juice.
Roll out the puff pastry until it is about 1/4 inch thick. You can use a wine bottle if you do not have a rolling pin.
Pour the cherry mixture into the center of the puff pastry leaving ~1-inch border. Fold over the puff pastry edges over the cherries.
Brush the edges of the puff pastry with the egg wash.
Bake 25-30 minutes until the puff pastry is golden brown.
If you have a baking steel, you can bake this galette on top of the steel to ensure you do not get a soggy bottom!This recipe also works with regular cherries if you're looking for something sweeter.Serve with your favorite vanilla ice cream!