Instead of using fresh mozzarella for this appetizer, try another fresh soft cheese, such as queso fresco or feta.
Set aside several whole basil leaves for garnish. Using a sharp knife, chop remaining basil leaves. Combine chopped basil, oil, vinegar, and pepper in a medium bowl. Cut mozzarella into 1-inch cubes; toss cheese cubes gently with herb and oil mixture until cheese is well-coated. Cover and chill for 1 hour or up to 5 days.
Transfer cheese mixture to a serving dish; garnish with basil leaves and, if desired, tomato slices. Serve with baguette slices or crackers. Makes 14 to 16 servings.