Turn the oven temperature to 350 F. Line a small rimmed baking sheet with parchment paper.
Slice a 5" section off of a loaf of Italian bread. Slice the bread in half lengthwise. Carefully cut 3/4 of the way down the middle of each half, leaving the bottom of the bread still intact. (See photos in blog post for reference.) Set aside.
Place the softened butter and roasted garlic cloves in a small bowl. Smash the garlic into the butter until thoroughly mixed. Stir in the parmesan, crushed red pepper, salt, pepper, garlic powder, and parsley until completely combined.
Divide the roasted garlic butter between the bread slices. Top the bread with the shredded mozzarella, dividing it equally over each slice.
Bake at 350 F for 10 minutes. Switch the oven to broil, and broil for 2-3 minutes until the cheese is bubbling.**
Remove from the oven, and sprinkle with more freshly chopped parsley (if desired). Serve hot!