Preheat oven to 375°F. In a medium bowl, stir together the halved cherries, maple syrup, vanilla extract, and tapioca flour. Toss until coated. Add in the chocolate chunks, reserving some to put on top. Set aside for now.
Roll the dough out between two pieces of parchment paper into a circle, about 10” across. You want it thick enough to be able to hold the filling and fold up the sides. Slide the parchment paper onto a baking sheet.
Brush the outside edges of the galette with some non-dairy milk (optional, gives it a little sheen). Let dry for two minutes, and brush one more time.
Bake for 30 minutes until the edges are golden brown. Remove from the oven and let cool for 10 minutes before slicing and serving. Store leftovers tightly sealed in the refrigerator.