Preheat oven to 425 degrees F and line a baking sheet with parchment paper or silpat mat.
Roll out prepared pie crust on a well-floured surface and roll out any existing creases. With a 3 inch heart cookie cutter, cut out as many hearts as you can. You will probably get around 8 from each pie crust.
Transfer half of the hearts on a baking sheet. Place about a tablespoon of the cherry pie filling in the center of each heart.
Place the remaining heart halves on top of the cherry filled hearts and gently press the edges down with a fork to make a crimp to seal the pies. Don't worry if a little pie filling comes out!
Brush the tops of the cherry pies with the beaten egg and bake for 12-14 minutes or until the tops of the pies turn a light golden brown. If you prefer to leave the icing off, you can top the pies with sprinkles or sugar.
To make the icing, whisk all of the ingredients in a bowl until smooth and no lumps remain. Drizzle or frost the pies with a spoon or butter knife. Top with sprinkles or enjoy as is!