Wash the tomatoes. Caramelise the sugar at medium heat in a pan until golden. Deglaze with vinegar. Bring to the boil and simmer over medium heat for 2-3 minutes, stirring continuously, until the sugar has dissolved.
Season to taste with salt and pepper.
Add the tomatoes to the stock and bring to the boil. Simmer for 4-5 minutes until they burst and drizzle with 1 tablespoon of oil. Remove from heat.
Cut buffalo mozzarella into 8 slices. Wash basil, shake dry, pluck off leaves and chop coarsely. Mix 2 tablespoons of oil and basil. Turn the mozzarella in it.
Pile up the tomatoes and mozzarella into small towers. Sprinkle with sea salt and coarse pepper.