Preheat oven to 350 degrees. Start with a French or sourdough loaf of bread or round boule. Cut the bread into 1" diagonal cuts but don't cut all the way through the bread.
In a microwave-safe bowl, melt the butter, garlic, and parsley together.
Using your fingers, open up each of the cuts and drizzle garlic butter into each of the pieces of bread. Press mozzarella cheese into each piece.
Brush the top of the bread with the remaining garlic butter and cheese. Wrap with foil and bake for 20 minutes. Remove from oven and open the foil and cook for 5-10 minutes longer until toasty.
Notes
I found that by grating your own cheese, it melts better rather than using pre-shredded mozzarella cheese.