Preheat your oven to 400 degrees.
In a small bowl, combine the softened butter, grated Parmesan, chopped parsley, grated garlic, and garlic powder. Season the mixture with salt and pepper.
Slice the loaf of bread into 1-inch thick pieces, being careful not to cut all the way through to the bottom.
Create a crosshatch pattern by making additional 1-inch thick slices perpendicular to the first cuts.
Place the loaf on a large piece of foil. Use a teaspoon or an offset spatula to spread the butter mixture generously on all the cut sides of the bread, ensuring you reach the bottom of each slice. Don't forget to coat the top of the loaf with some of the butter as well.
Sprinkle the grated mozzarella cheese between the slices of bread.
Wrap the loaf tightly in the foil and place it on a baking sheet. Bake in the preheated oven until the mozzarella begins to melt, which should take about 20 minutes.
Unwrap the bread and continue baking until the cheese is fully melted and the top is golden and crispy, approximately 10 to 15 more minutes.
Enjoy your cheesy pull-apart bread!