In a mixing bowl, combine softened cream cheese, grated Parmesan, mayonnaise, garlic powder, onion powder, and black pepper. Stir in the thawed and dried frozen spinach until smooth.

On a lightly floured surface, unroll the puff pastry sheet. Using a rolling pin, stretch it to smooth out creases and create an even rectangle. Spread the spinach mixture across the pastry, leaving about an inch margin on one edge.

Starting from the filling edge, roll the pastry tightly towards the empty edge, keeping the filling inside. Aim for a firm roll.

Wrap the rolled pastry log in plastic wrap and refrigerate for at least 30 minutes.

Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.

Remove the log from the refrigerator and slice it into half-inch rounds. Place the pinwheels on the baking sheet and brush the tops with egg wash.

Bake for 15-20 minutes, or until golden brown. Allow to cool slightly before serving.