In a bowl, combine the softened cream cheese, grated Parmesan cheese, mayonnaise, garlic powder, onion powder, and black pepper. Mix well until everything is evenly blended.

Squeeze out as much excess water from the thawed spinach as possible and add it to the cheese mixture. Stir until completely combined.

Flour your counter and roll out the sheet of puff pastry. Spread the spinach mix evenly over the pastry, leaving one long edge empty to seal later.

Starting from the filled edge, roll it up tightly like a jelly roll.

Wrap the rolled pastry log in plastic wrap and refrigerate for about 30 minutes to firm it up. Preheat your oven to 400°F (200°C) while you wait.

After chilling, take the log out of the fridge and slice it into half-inch rounds.

Place them on a baking sheet lined with parchment paper. Brush each pinwheel with the beaten egg mixture.

Bake in the preheated oven for 15-20 minutes, until they puff up and turn golden brown.