Preheat the oven to 375°F. Prepare 2 baking sheets by lining them with silicone baking sheets or parchment paper.
Dust your rolling area, parchment paper or pastry mat with flour. Place the puff pastry on top and lightly dust the top of the dough with flour. Roll into a 10- to 12-inch rectangle.
Divide the pesto for each sheet and spread the pesto over each pastry sheet to the edges. Sprinkle an even layer of parmesan over the pesto and puff pastry. Divide the rendered pancetta over each sheet. Next, add a generous amount of fresh cracked black pepper to each.
Cover the puff pastry with a sheet of parchment paper and lightly press the toppings into the pastry.
Using a sharp knife or pastry cutter, slice each puff pastry crosswise into 8 strips. Twist each strip into a spiral and transfer to the parchment-lined pans. Be sure to leave about 1 inch of space between each strip. Brush the puff pastry with the egg wash and dust again with pepper.
Bake for 18 minutes, or until the straws are puffed and golden brown. Serve immediately.