In a small sauce pan, bring balsamic vinegar to a boil over medium-low heat. Cook for 10-20 minutes, or until balsamic reduces and becomes a thick glaze.
Remove to a bowl and let cool.
Place tomatoes and mozzarella slices on a platter alternating between tomato and mozzarella.
Arrange basil evenly through out the salad.
Drizzle with olive oil and balsamic reduction.
Sprinkle with salt & pepper.
Serve and enjoy!