Preheat your oven to 375°F (190°C).
In a small bowl, mix the softened butter, minced garlic, parsley, salt, pepper, and chili flakes.
Slice the bread loaf in half lengthwise and spread the garlic butter mixture evenly on both halves.
Sprinkle the shredded mozzarella and grated parmesan cheese over the buttered bread.
Place the bread on a baking sheet and bake for 12–15 minutes, or until the cheese is melted and bubbly.
For an extra golden crust, broil for 1-2 minutes at the end.
Take it out of the oven, allow it to cool for a minute, then cut it into slices and serve.