01 - Preheat the oven to 400°F (200°C) and line a baking sheet with parchment paper.
02 - Slice the baguette in half lengthwise, then cut each half into 4 pieces, yielding 8 slices total.
03 - Combine softened butter, minced garlic, parsley, chives if used, salt, and pepper in a bowl until well incorporated.
04 - Spread the garlic butter evenly over the cut sides of each bread slice.
05 - Sprinkle shredded mozzarella evenly over each slice, then top with grated Parmesan.
06 - Place the bread slices cut side up on the prepared baking sheet.
07 - Bake for 10 to 12 minutes until cheese melts and turns lightly golden. Optionally, broil 1 to 2 minutes more for extra crispness, watching closely.
08 - Remove from oven, let cool slightly, and serve warm.