Prepare the dough: Roll out the pizza dough on a lightly floured surface and divide it into 30 even pieces. Flatten each piece slightly with your fingers.
Add the cheese: Place a cube of mozzarella in the center of each dough piece and wrap the dough around it, pinching tightly to seal so the cheese stays inside while baking.
Shape the tree: Line a baking sheet with parchment paper. Arrange the dough balls seam-side down in the shape of a Christmas tree—starting with one ball at the top and building rows that increase in width. Add a small row of two dough balls at the bottom for the tree trunk.
Brush with garlic butter: In a small bowl, stir together the melted butter, half of the Parmesan, Italian seasoning, and grated garlic. Brush the mixture generously over the dough balls.
Bake: Bake at 400°F (205°C) for 18–22 minutes or until the tops are puffed and golden with bits of melted mozzarella peeking out.
Finish: Remove from the oven and sprinkle with the remaining Parmesan and parsley. Serve warm with a bowl of pizza sauce for dipping.