Preheat Oven & Prepare Baking Tray:
Preheat oven to 375°F (190°C). Line a baking tray with parchment paper.

Make the Filling:
In a mixing bowl, combine cream cheese, shredded white cheese, Parmesan, and garlic (if using). Stir in the well-drained spinach, salt, and pepper until smooth.

Assemble the Pinwheels:
Lay the puff pastry sheet flat on a lightly floured surface. Evenly spread the cheese and spinach mixture, leaving a 1-inch border on one edge.

Roll & Slice:
Tightly roll the puff pastry from the opposite edge of the border. Press to seal, then slice into ½-inch-thick rounds using a sharp knife.

Bake:
Arrange pinwheels on the prepared baking tray, leaving space between them. Bake for 20-25 minutes, or until the pastry is puffed and golden brown.

Cool & Serve:
Let cool slightly before serving. Enjoy warm as an appetizer or snack!