First, thaw your puff pastry sheets according to package instructions. Lightly flour your surface and roll the sheets into rectangles if needed. This ensures even layers and easy rolling.
Spread a thin, even layer of basil pesto over each puff pastry sheet. I like to leave a small border around the edges so the filling doesn’t ooze out while baking.
Sprinkle shredded mozzarella and grated Parmesan over the pesto. Then scatter chopped sun-dried tomatoes evenly. I find pressing the toppings lightly helps them stick during rolling.
Carefully roll the pastry lengthwise into a tight log. Chill the log for 10–15 minutes—it makes slicing much cleaner. Then cut into 1-inch pinwheels with a sharp knife or pizza cutter.
Brush each pinwheel with the beaten egg to get a golden, glossy finish. Don’t skip this step; it makes the pinwheels look bakery-worthy.
Place pinwheels on a parchment-lined baking sheet, leaving a little space between each. Bake at 400°F (200°C) for 18–20 minutes or until golden and puffed. I usually watch the last 5 minutes closely to avoid over-browning.