Preheat oven to 400°F and line a baking sheet.
Roll puff pastry into a 12×16-inch rectangle.
Spread pesto over pastry, leaving a border.
Sprinkle mozzarella and Parmesan on top.
Cover with second pastry sheet, pressing edges to seal.
Cut into a Christmas tree shape and twist branches.
Brush with egg wash and season with salt and pepper.
Add cherry tomato halves and bake 20–25 minutes until golden.
Cool slightly, garnish with basil, and serve warm.