For the soup

1 large potato, cut into cubes
1 onion, chopped
4 small cucumbers, peeled, deseeded and cut into cubes
3-4 large romaine lettuce leaves, chopped
1lt. warm vegetable stock
2 tbsp chopped mint, parsley, dill or basil
olive oil, salt, pepper

For the tomato vinaigrette

1 large tomato, peeled and deseeded
2 tbsp olive oil
1tbsp balsamic vinegar