1. First, make the dressing by putting the shallots, vinegar, salt and sugar into a small mixing bowl.
2. Gradually add the oil so that vinegar emulsifies with the oil.
3. Keep to one side to allow the flavours to get to know each other.
4. In the meantime, arrange the tomatoes on a large platter.
5. Scatter the olives and capers and basil evenly over the tomatoes.
6. Season with some salt and pepper. Whisk the dressing once more then drizzle over the salad.