Stir fried ginger and onion until fragrance. Add all zucchini. Cover with lid until soft. Add tomatoes, covered for 2 minutes.

Add water, vinegar and pepper. Boil for 2 minutes.

Add soft tofu, careful not to break them.

Lightly whisk egg with pepper and salt. Pour it over soup with continuous moving motion.

Add more water if prefer a more watery style. Add vinegar if prefer more sour taste.