I followed Sally's Baking Addiction recipe for handmade puff pastry here and then used the following method for the pesto mozzarella & braiding:

steps

1. Preheat oven to 400F. 

2. In a small bowl, mix 2 tbsp pesto with about 1/2 cup shredded mozzarella. Stir until thoroughly combined.

3. After rolling out the pastry dough, use a knife or dough scraper to cut an equal number of cuts into the two sides of the pastry dough. Each cut should be about 1/3 of the width of the pastry dough sheet so you end up with 1/3 of uncut space in the middle.

4. Spread the pesto mozzarella into the center of the pastry dough where there are no cuts.

5. Alternating sides, pull each pastry cut strand across to create a zigzag pattern over the pesto mozzarella. Pinch together the open ends and tuck underneath to seal.

6. Apply an egg wash (1 beaten egg) over the pastry.

7. Bake for 25-30 minutes or until pastry is golden brown.