Using a serrated knife, slice the tomatoes horizontally about 1/2 inch thick. Discard the very tops and the bottoms.
Using a sharp knife, slice the mozzarella into 1/4-inch slices.
On a large plate or platter, arrange the tomato and cheese slices in an alternating shingle pattern.
Place the basil leaves in a blender with the olive oil and puree until smooth, about 15 seconds.
Drizzle the basil oil evenly over the tomatoes and mozzarella. In a small mixing bowl, combine the balsamic vinegar and the sugar and whisk to combine. When the sugar is completely dissolved, pour the vinegar mixture over the tomatoes and mozzarella.
Garnish the plate with fresh basil leaves and sprinkle with salt and black pepper to taste. Serve immediately.
Yield: 4 - 6 servings