Preheat the oven to 400°F.
Thaw your puff pastry as per the package instructions and dust your board, counter, or to save time you can do this straight onto a baking sheet lined with parchment paper too.
I place my puff pastry on top and I fold all the edges about a quarter inch towards the middle.
I take a fork and dip it in flour and a crimp the edges all around.
In a separate bowl whisk one egg with a little bit of water and brush it all around the border.
To make the filling add the mozzarella, egg, feta, and spinach into a separate bowl and mix it together.
Add the filling to the middle of your pastry and spread it in the middle within the square with a spoon.
Bake at 400F for 20-25 minutes or until golden.
Optionally broil for 1 minute on top but watch it the whole time.
