Heat a medium sized sauce pan and add butter to it. Let it melt and bubble and then add chopped apple, brown sugar, cinnamon & vanilla extract.Cook on medium heat until apple is half cooked about 7-8 minutes. Add cornstarch mixed with water and stir. Let it come to a boil and then remove from heat.Transfer in a heatproof container and let it cool to room temperature.
Roll out pie dough or puff pastry dough on a lightly floured surface ⅛t inch thick. Keep the dough in rectangle shape and cold during the process.
Cut out 12 discs that are 3 inch wide with the help of a cookie cutter and transfer it on a baking tray lined with baking paper.
Spoon the apple filling (2 tablespoons) on 6 discs leaving some space around the edges. Brush milk around the edges and Cover the top with the remaining 6 discs of dough. Use a fork to press and seal the edges and make sure the edges are sealed and cut 3 tiny slits on the top with a knife for steam to escape.
Brush the tops lightly with maple syrup. Sprinkle turbinado sugar / cane sugar and bake in a pre heated oven at 375f for 15-17 minutes until they're golden brown.
