In a mixing bowl, combine the cherries, sugar, cornstarch, lemon juice, and vanilla extract. Stir until well mixed.

Let the mixture sit for about 10 minutes to allow the cherries to release their juices.

Preheat the oven to 375°F (190°C).

Roll out the pie crusts on a floured surface and cut them into 4-inch circles.

Place a spoonful of the cherry filling in the center of each circle.

Fold the dough over the filling to create a half-moon shape and seal the edges by pressing with a fork.

Brush the tops with the beaten egg and sprinkle with sugar.

Place the filled pastries on a baking sheet lined with parchment paper.

Bake in the preheated oven for 15-20 minutes or until golden brown.

Remove from the oven and let cool slightly before serving.