Preheat the oven to 400 F. On a lightly floured surface, roll out both pie sheets to about an 8 X 16 inch rectangle. Transfer one of the sheets to a baking sheet lined with parchment paper. Spread the filling on top, leaving about a half inch of space around the edges. Carefully place the other sheet of pie dough over top so it overlaps. Use a sharp knife to trim around the sides if needed. With a fork, press down around all sides of the giant pop tart to seal it together. Poke a few holes in the middle of the pop tart so air can escape. Whisk an egg in a bowl for the egg wash (optional) and brush over the entire pop tart. Bake the pop tart in the oven for 15 - 20 minutes until golden brown. Allow it to cool down off to the side.

Once the pop tart has cooled down, prepare the icing by mixing together the Chocolate SunButter, powdered sugar, cocoa powder, milk, and vanilla extract in a bowl until smooth. You’re looking for a glue-like consistency. If the icing is too thin, add another sprinkle of powdered sugar. If it’s too thick, add a small splash of milk. Gently spread the icing over the top of the pop tart, leaving some room around the edges. Sprinkle some flaky sea salt over top and allow the icing to set for a few minutes before slicing into pieces.