Heat oven to 350 degree F. Combine butter, garlic and basil in a small bowl.
With serrated knife, slice bread lengthwise in half horizontally. Slice each half into 12 pieces, without cutting completely through bottom crust. Place on large piece of nonstick foil. Brush butter-garlic mixture over bread. Place mozzarella slices on top, then sprinkle evenly with Parmesan.
Unwrap bread, if necessary. Place bread on foil on a large baking sheet. Bake at 350° for 10 to 15 minutes until cheese is melted. Let cool slightly, then serve.