Preheat oven to 375°F. Line baking sheet with parchment.
Mix spinach, cream cheese, mozzarella, Parmesan, garlic powder, onion powder, salt, and pepper.
Roll puff pastry into a triangle. Place on baking sheet.
Spread spinach dip evenly over triangle.
Roll out second pastry sheet, cut into triangle, and place on top. Trim to match.
Cut horizontal strips on sides, leaving center intact. Twist strips to form branches.
Brush tree with garlic butter.
Bake 30–35 minutes until golden brown.
Cool 5 minutes before serving warm.