Preheat the oven to 375°F (190°C). Line a baking sheet with parchment paper.
In a medium bowl, combine the softened cream cheese, shredded mozzarella, grated Parmesan, sour cream, and minced garlic. Mix until smooth.
Add the chopped spinach, chopped artichoke hearts, salt, black pepper, and dried Italian seasoning to the cheese mixture. Stir until well combined.
Unfold the thawed puff pastry sheet on a lightly floured surface. Using a rolling pin, gently roll it out into a 12×10 inch rectangle.
Spread the spinach and artichoke cheese mixture evenly over the puff pastry, leaving a small border around the edges.
Starting from one long edge, carefully roll the puff pastry into a tight log.
Using a sharp knife, slice the log into 12 equal pinwheels, about 1 inch thick each.
Place the pinwheels cut side up on the prepared baking sheet, spacing them about 1 inch apart.
Brush the tops of the pinwheels with the beaten egg to give them a golden finish.
Bake in the preheated oven for 18-20 minutes, or until the pinwheels are puffed and golden brown.
Remove from the oven and let cool for 5 minutes before serving.