Preheat Oven: Preheat oven to 375°F (190°C). Line a baking sheet with foil.
Prepare the Bread: Using a sharp bread knife, cut the loaf in a crosshatch pattern slice almost to the bottom but not through, making 1-inch wide sections.
Mix Garlic Butter: In a small bowl, combine melted butter, garlic, parsley, Italian seasoning, salt, and pepper.
Stuff with Cheese: Gently pull bread sections apart and stuff mozzarella and Parmesan evenly between the cuts.
Add Garlic Butter: Drizzle or brush the garlic butter mixture into all the crevices of the bread.
Wrap and Bake: Wrap the loaf loosely in foil and bake for 15 minutes.
Uncover and Finish Baking: Open the foil and bake for another 10 minutes, or until cheese is fully melted and the bread edges are crispy.
Serve: Garnish with extra parsley and serve immediately while warm and gooey.