Once the peaches have cooled, preheat the oven to 400℉/200℃ and line a large baking tray.
Remove the puff pastry from the refrigerator (it needs to be cold when you start this step). Roll flat and cut out about 12 circles using a cookie cutter/jar/glass. Place 6 of these circles onto the lined baking tray.
Top each of those 6 circles on the baking tray with a large teaspoon of the peach pie filling.
Top the pies with the other 6 circles of puff pastry and crimp to close using a fork. For the golden shine: beat the egg in a small bowl then brush onto the pastry. Top with a sprinkle of granulated sugar prior to baking.
Bake 15-17 minutes - until the pies are golden brown! Remove and let cool on a wire rack - dust with powdered sugar for a little extra sparkle!