In a mixing bowl, combine the thawed spinach, sundried tomatoes, mayonnaise, grated Parmesan cheese, onion powder, garlic powder, and black pepper. Mix well until all ingredients are thoroughly combined.
Unroll the puff pastry sheets on a lightly floured surface. Use a rolling pin to gently roll out each sheet to smoothen any creases and slightly increase the size.
Evenly spread the spinach and sundried tomato mixture over each sheet of puff pastry, leaving a small border around the edges.
Starting from one end, carefully roll the puff pastry sheet away from you, creating a tight log. Make sure to pinch the seams to seal the roll.
Using a sharp knife or pizza cutter, slice the rolled pastry into 1-inch thick pinwheels. You should have about 12-15 pinwheels from each sheet.
Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper and arrange the pinwheels on the sheet, spacing them about an inch apart. Bake for 15-20 minutes, or until they are golden brown and puffed.
Once baked, remove the pinwheels from the oven and let them cool for a few minutes. Serve warm, and enjoy the delightful flavors of your Spinach and Sundried Tomato Puff Pastry Pinwheels!
