Preheat oven to 400℉.
Roll both sheets of puff pastry dough into 12x10 inch rectangles with a rolling pin, then cut each sheet into 6x equal rectangles (12 total – 6 for top, 6 for bottom).
Spoon 1 tablespoon jam into the center of 6 of the puff pastry rectangles, then spread it out using the back of a spoon or knife, leaving ½” border around the edge.
In a small bowl whisk together the egg and a dash of water.
Brush the egg wash around the edge of each pastry
Top each of the 6 pastries with the remaining 6 and crimp the edges using a fork to seal them together.
Brush egg wash over the tops of the pastries and slice a slit in the center for some air to escape.
Bake in a preheated oven at 400°F for 15 minutes until deeply golden.
In a small bowl, mix together all ingredients for the icing.
Let the pastries cool a bit and then drizzle over top of each pop tart.