When ready to proceed with baking, prepare each filling (filling recipe below). Roll out each dough piece between two sheets of lightly floured parchment paper.
Use a salad plate or other 8 inch round item as a template for each galette disc. You will need to re-roll the excess dough to make the fifth disc.
Place each disc on a parchment lined baking stone or baking sheet or lay two side by side on a large baking sheet.
Preheat the oven to 400 degrees F, with oven rack in center position.
Mound the filling, mixing the fruit fillings as you choose into the center of each disc and leaving a 1 ½ - 2 inch edge free of any filling. Place the apples or strawberry filling at the bottom of the crust for any combination of apple or strawberry with blackberry, to keep the filling from leaking out. Top with 2 tablespoons of butter divided between the 4 or 5 mini galettes.
Fold the pastry dough from the outside towards the center of the disc. The dough will not cover the filling, but will leave a 2 ½ - 3 inch hole without dough. Brush the dough with 1 tablespoon of egg white mixed with 1 tablespoon of water. Seal and make any repairs of cracks with the egg white mixture and excess dough pieces or a dab of gluten free flour. Shake a teaspoon of sugar over the top and crust of each galette.
Bake for 40-45 minutes each until the filling is bubbly and the crust is golden brown, rotating two trays in the oven halfway through baking. When you remove the trays to flip their position, brush the crust with a little milk or half and half. For the apple galette, drizzle 1 ½ tablespoons of honey over the filling. Return to the oven in the alternate position to finish baking. Refrigerate any galettes that will wait for oven space until others have been baked. Serve while warm or at room temperature with plenty of gluten free ice cream or barely sweetened whipped heavy cream.