Add pitted cherries, sugar, coconut flour and cherry juice to a bowl; toss well and set aside for at least 30 minutes. Meanwhile, place pie dough onto parchment lined baking sheet, unfold and press together any cracks or breaks; place in refrigerator for 30 minutes. Preheat oven to 400°F. Remove dough from refrigerator, place cherry filling in the center of dough and sprinkle with diced butter. Use the parchment as a guide to fold the dough up and pinch around cherries to form an open top shell. Gently lay the parchment back down once the shell has been formed. Pinch together any breaks in the shell to hold juices in. In a small bowl, combine 1 egg with 1 tablespoon of cold water to create an egg wash. Brush dough shell with egg wash and sprinkle with turbinado sugar. Place in oven and bake for about 35 to 40 minutes or until crust is golden brown and juices are bubbling. Remove from oven and rest for at least 10 minutes before slicing.