In a medium mixing bowl, combine the spinach, cream cheese, mozzarella, Parmesan, garlic powder, onion powder, salt, and pepper. Mix until well blended.
Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper.
Roll out one puff pastry sheet on a lightly floured surface. Shape it into a large triangle, which will form the base of the tree. Place it on the prepared baking sheet.
Spread the spinach dip evenly over the puff pastry triangle.
Roll out the second puff pastry sheet and cut it into another large triangle, then place it over the spinach dip-covered triangle. Trim the edges to match the shape of the bottom triangle.
Using a sharp knife, cut horizontal slits on both sides of the triangle, leaving the center intact to form the tree trunk. These slits will be the branches.
Twist each strip a few times to create a spiral effect, resembling tree branches.
In a small bowl, combine the melted butter and garlic powder. Brush this mixture over the puff pastry.
Bake in the preheated oven for 30-35 minutes, or until the pastry is golden brown and puffed.
Then let it cool for about 5 minutes before serving.
Serve warm and enjoy your festive Christmas tree spinach dip puff pastry with family and friends!