Preheat your oven to 400°F and line a baking sheet with parchment paper.

In a hot skillet, sauté baby spinach with a pinch of garlic powder until just wilted, about 2 minutes; drain any excess liquid.

In a bowl, stir together softened cream cheese, shredded mozzarella, grated Parmesan, salt, and pepper until smooth; gently fold in wilted spinach.

Lightly dust a clean surface with flour, then unfold each puff pastry sheet into a flat rectangle.

Evenly distribute the cheese-spinach mixture over each pastry, leaving a ½-inch border.

Starting from one long edge, tightly roll each pastry into a log; refrigerate 10 minutes, then slice into 1-inch pinwheels.

Place pinwheels cut-side up on the prepared sheet; brush tops with beaten egg.

Transfer to oven; bake at 400°F for 15-18 minutes until golden brown and cheese bubbles through.