01 - Preheat the oven to 375°F and line a baking sheet with parchment paper.
02 - Slice the baguette lengthwise, placing both halves cut side up on the baking sheet.
03 - Combine softened butter, minced garlic, chopped parsley, salt, and black pepper in a small bowl until uniform.
04 - Evenly spread the garlic butter mixture over the cut sides of the bread halves.
05 - Distribute shredded mozzarella, cheddar, and grated Parmesan evenly over both bread halves.
06 - Bake for 15 to 20 minutes until the cheese is melted, bubbly, and the edges turn golden brown.
07 - Optional: Broil for 2 minutes while monitoring closely to achieve extra crisp edges without burning.
08 - Remove from oven, allow to cool briefly, then slice into 8 portions and serve warm.