Preheat the oven to 375F, and line two baking sheets with parchment.
First, prepare the filling. Rinse the berries well, cut them in half, and place them in a medium bowl. Add in the sugar, lemon juice, cinnamon, and flour, and mix well.
On a well-floured surface, lay out the pie crusts and gently roll them out to ¼" thickness.
Using a large cookie cutter or other round object, cut out circles about 5 inches across.
Place the circles of dough on the baking sheets, and spoon about 1 tablespoon of filling in the center of each.
Fold the dough over, and press the edges firmly with your fingertips to seal. Using a knife, gently cut 2-3 small slits on the top of each pie. Brush them with the beaten egg, and sprinkle a little bit of sugar on top.
Bake for about 20 minutes, until golden brown and flaky. Let cool slightly, and enjoy!