Pain au Chocolat

1 (17.3oz) package puff pastry sheets, thawed
1 1/2 cup semi-sweet chocolate chips
1 egg, beaten
2 tbsp butter
1 cup powdered sugar
2-3 tbsp warm water

Preheat oven to 350.
Unfold each sheet of puff pastry onto a floured surface, and roll each into a 10-inch square.
Use a pizza cutter to cut each piece of puff pastry into 4 5-inch squares, for a total of 8 squares.
Place 2 tbsp of chocolate chips in the center of each square.
Brush the edges of each square with the egg, fold over, and press to seal.
Place the pastries on a foil-lined baking sheet, and brush the tops of each one with the remaining egg.
Bake for 15-18 minutes, or until the tops are golden brown.
Allow the pastries to cool completely on a wire rack. While they are cooling, melt the remaining chocolate chips and butter on low heat, stirring until smooth.
Add in the powdered sugar and water, stirring until silky.
Place a small Ziploc bag into a glass, and turn over the top edge of the bag. Pour the chocolate into the bag, and gather the top, to use like an icing bag.
Cut one corner of the bag, and drizzle the chocolate on top of each pastry.