Heat oven to 350 degrees F. Cut out 12 (4-inch) circles from the pie crusts using the top of a large cup, a cookie cutter, or a bowl, rerolling dough as needed. Set aside.
In a mixing bowl, combine the pumpkin puree, cream cheese, sugar, pumpkin pie spice, and egg. Set aside.
Using the rolling pin again, gently roll out each circle just a little more to create a crust slightly thinner than a regular pie crust. Evenly distribute the pumpkin filling between the 12 dough circles, placing the filling on one half of the circle. Gently fold the dough over the filling. Using a fork, press the edges of the dough together, sealing the filling inside.
Using a sharp knife, cut a few slits across the top of each pasty. Place each pasty on a baking sheet. Using a pastry brush, lightly coat each pasty with melted butter. Sprinkle the top of each pasty with sugar crystals, cinnamon sugar, or colored sugar sprinkles, if desired.
Bake for 25-30 minutes or until pasties are lightly browned.