As a note, I like to use puff pastry that comes in one full sheet, such as wewalka or jus rol. If you buy one that is perforated, I suggest rolling it out a bit with a rolling pin so it’s one long sheet.
Preheat the oven to 425 degrees F. Line a baking sheet with parchment paper.
Heat the olive olive in a skillet over medium-low heat. Add the garlic and cook for 30 seconds.
Add in the broccoli with a pinch of salt and pepper. Cook until slightly softened, about 3 to 4 minutes. Stir in the pepper flakes.
Slice the puff pastry in half lengthwise. Keep one piece on the parchment paper.
Sprinkle the mozzarella cheese on the one long sheet of puff pastry, leaving a ½ inch border. Top with the broccoli in an even layer. Sprinkle the parmesan on top.
Use the egg wash to brush the border of the puff pastry. Place the other slice of puff pastry on top, pressing down the edges to seal.
Slice a few slits in the top to let steam escape.
Bake for 20 to 25 minutes, until golden and puffed. Remove and let cool slightly before sprinkling with parmesan. Slice and serve!