Preheat your oven to 350°F (175°C).
In a small bowl, melt the butter in the microwave or on the stove over low heat. Once melted, stir in minced garlic, parsley, salt, and black pepper.
Carefully cut the bread into 1-inch cubes, making sure to cut down to the base but not through it, keeping the loaf intact.
Place the loaf in the baking dish and gently pull apart the pieces to create gaps for the cheese and butter mixture.
Pour the garlic butter mixture evenly over the bread, ensuring it seeps into the cracks.
Stuff the shredded mozzarella and cheddar cheese into the gaps of the bread, packing it in generously.
Cover the baking dish with aluminium foil and bake for 20 minutes.
Remove the foil and bake for an additional 10-15 minutes, or until the cheese is melted and bubbly and the top is golden brown.
Let the bread cool for a few minutes before serving. Serve warm, pulling apart the pieces to enjoy!