Preheat oven or grill to 450 degrees Fahrenheit.
Cut off the top of the garlic horizontally, about 1/4 of the way down from the top of the bulb to expose the top of the cloves. Drizzle with olive oil, and sprinkle with salt and pepper.
Wrap garlic in a sheet of aluminum foil and roast in the oven or over indirect heat on the grill, approximately 20 minutes or until the garlic is brown and soft.
Remove garlic from oven or grill, and let cool. Lower oven or grill temperature to 400 degrees Fahrenheit.
From the block of mozzarella, make about 12 1/8" slices of cheese and set aside.
Once the garlic is cooled, "squeeze" out the cloves from the bulb, or remove them with a fork, discarding any papery skin of the garlic.
Add garlic, butter, Italian seasoning, 1/4 cup parmesan cheese, and 1/2 teaspoon each salt and black pepper to a food processor or mini chopper. Pulse until well combined.
Slice a loaf of crusty Italian bread horizontally, not cutting all the way through, making about 12, 1" slices through the entire loaf.
Spread the garlic butter mixture between the slices and add a slice of mozzarella until the entire loaf of bread is filled. Sprinkle with remaining Parmesan, salt and pepper.
Wrap bread in a sheet of aluminum foil, and bake at 400 degrees F for approximately 10-15 minutes or until the bread is hot and the cheese has melted.