Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper or a silicone baking mat.
Make sure your puff pastry sheet is fully thawed but still cold to make it easier to work with.
Lightly flour your work surface and roll out the puff pastry sheet into a rectangle about 12x10 inches.
Spread the pesto sauce evenly over the entire surface of the puff pastry using a spatula or the back of a spoon.
Distribute the halved cherry tomatoes evenly over the pesto-covered pastry, cut side up.
Sprinkle the shredded mozzarella cheese generously on top. Season lightly with salt and pepper.
Slice the puff pastry into long strips about 1 inch wide using a sharp knife or pizza cutter.
Take each strip and twist it several times to create a spiral effect. Place twists on the prepared baking sheet, spacing about an inch apart.
Brush the beaten egg over each twist gently to give a golden-brown color and shine when baked.
Bake for 15-20 minutes or until the pastry is puffed, golden brown, and cheese is melted and bubbly.
Remove from oven and let cool for a few minutes. Garnish with fresh basil leaves and serve warm.