Preheat the oven to 375° F. and line a baking sheet with a slice of aluminum foil.
Using a serrated knife, slice the bread loaf into even slices. Don't cut the bread loaf all the way through, however.
In a small bowl, make the garlic butter by stirring together the softened butter, extra virgin olive oil, garlic powder and chopped parsley until spreadable.
Using a knife, spread garlic butter down into each slice on the bread loaf, reserving about half for later.
Stuff a slice of mozzarella cheese down into each sliced opening of the bread loaf.
Spread remaining garlic butter all over the top of the bread loaf.
Sprinkle the top with parmesan cheese.
Bake for 25 to 30 minutes, until cheese is melted and bread is golden brown.