Preheat oven to 175 degrees Celsius (350 degrees Fahrenheit).

Using a serrated knife, cut the bread in a 1-inch crosshatch pattern, slicing deep but not through the bottom crust.

In a small bowl, combine softened butter, minced garlic, salt, red pepper flakes, and chopped parsley.

Gently pull apart the bread segments and spread the garlic butter mixture into the crevices using a butter knife.

Stuff the shredded mozzarella and parmesan cheese into the cuts, ensuring even distribution throughout the loaf.

Wrap the entire loaf in aluminum foil and place on a baking sheet.

Bake for 15 minutes.

Remove the foil from the top and bake for an additional 5 minutes until the cheese is bubbling and bread is golden.

Serve immediately while warm.