Preheat your oven to 400°F.
Slice each French bread loaf in half lengthwise. Place the halves cut-side up on a baking sheet.
In a medium bowl, combine the softened butter, minced garlic, dried parsley, salt, and black pepper. Mix until well combined.
Spread the garlic butter mixture evenly over the cut sides of the bread.
Sprinkle the shredded mozzarella cheese and grated Parmesan cheese generously over the buttered bread. If desired, add red pepper flakes for a bit of heat.
Bake in the preheated oven for 10-12 minutes, or until the cheese is melted and bubbly and the edges of the bread are golden brown.
Remove from the oven and let cool for a couple of minutes before slicing into pieces. Serve warm.