Prepare pie crust for galettes. Unroll the refrigerated pie crust on parchment paper. Use a 5" to 6" bowl as a guide to cut out three circles in each pie dough crust. Line a sheet pan with parchment paper. Place your 6 circles on top and put the sheet pan in the fridge while preparing your filling.
Preheat oven to 375º F and gather your ingredients.
Zest one lemon and set aside. Then squeeze half a lemon and set aside.
Combine in a small bowl the sugar, cornstarch, cinnamon and salt.
In a medium size bowl add the dry mixture to the blueberries and mix together. Then stir in your fresh squeezed lemon juice and lemon zest.
Remove pie crust from the fridge. Spoon blueberry mixture in the center of a dough circle and fold over the pie crust. Continue until all are complete.
Beat egg for egg wash. Use a pastry brush to apply egg wash to the the folded pie crust, then sprinkle with sugar.
Place in a preheated 375º F oven and bake for 20 to 25 minutes or until bubbly and crust is golden brown.
Remove from oven and carefully place galettes on a cooling rack. Allow to cool slightly before serving.