Preheat oven to 350 degrees F. ad prepare a baking sheet by spraying generously with non-stick spray or line with parchment paper.
In a large mixing bowl, combine spinach, artichoke hearts, cream cheese, sour cream, garlic salt, and cayenne pepper. Mix until well combined.
Fold in parmesan and mozzarella cheese. Set aside.
Place one sheet of puff pastry on the prepared pan.
Spread the spinach mixture over the puff pastry in the shape of a large triangle.
Place the second sheet of puff pastry over the spinach dip.
Use a pizza cutter or a knife, carefully cut out the outline of the spinach dip. Discard any excess pastry.
At the base of the tree, carefully cut away the bottom strips leaving the “trunk” of the tree.
Cut 1-inch slits on both sides of the tree leaving about 1 inch in the center intact.
Starting from the bottom, take each slit and twist 1-2 times away from you. Continue all the way up the tree on both sides. On the smaller pieces you may only be able to twist once.
Brush the top of the pastry with the beaten egg and bake for 26-28 minutes or until the pastry is golden brown.
Once the pastry is done, add the melted butter, garlic salt, and parsley into a small bowl and brush all over the top of the pastry.
Serve immediately.