Preheat the oven to 350 degrees Fahrenheit.
Cut the bread diagonally, cutting down most of the bread, but not all the way through. Turn around and repeat in the other direction. (See photos in the post.)
16 ounces crusty artisan loaf
Melt the butter and whisk in the garlic, parsley, salt, and pepper. Brush the butter mixture into the cracks of the cut bread. Save a small amount, about 2 tablespoons, for the end.
8 tablespoons unsalted butter, 3 garlic cloves, 1 teaspoon dried parsley, 1 teaspoon kosher salt, dash black pepper
Mix the cheeses together and push them into the bread. Brush the final 2 tablespoons of the butter mixture onto the top of the bread.
1 1/2 cups mozzarella cheese, 1/2 cup Parmesan cheese
Cover loosely with aluminum foil and bake for 25 to 30 minutes, or until the cheese is completely melted. Serve immediately.