1 Heat the oil in a frying pan and gently fry the tomatoes (still on their stalks) for about 3 minutes, until they begin to soften.
2 Add the sugar, a little salt and the sliced garlic and cook for a further 2 minutes or so, until the sugar begins to caramelise. Take the tomatoes and garlic out of the pan and deglaze the caramel with vinegar.
3 Add the cheese and leave in the pan for about 1 minute, until it begins to melt. Do not turn over.
4 Arrange the washed watercress, tomatoes and garlic on a platter. Add the cheese and drizzle with the balsamic sauce.