If using frozen puff pastry, make sure to pull it out and let it thaw for 15-20 minutes.
Using a rolling pin, roll out your puff pastry slightly larger, adding another 2-3" to the height and width.
Place your massive Reese's in the middle.
With a sharp knife, round off the corners of the puff pastry slightly.
In a small bowl, mix together your egg and water to make your egg wash.
Using a pastry brush, spread a light layer around the perimeter of the puff pastry.
Starting at the top, bring the edge of the puff pastry to the center of the Reese's and press down slightly. Moving over about an inch, repeat the pattern until you have folded and pressed all the puff pastry down around the Reese's. *see video attached if you have questions*
Once the Reese's is completely covered, brush the top with egg wash as well and move to a 400-degree oven until crisp and golden, about 30-40 minutes.
Move to a plate, top with ice cream or your favorite sweet drizzle, and proceed to thoroughly enjoy.
Video
Notes
You can absolutely substitute normal-sized Reese's for this, or whatever holiday-themed Reese's that might be out. I'm looking at your Easter Egg and Christmas Tree Reese's.