Leek onions clean, wash, quarter lengthwise, then cut crosswise very finely. Peel garlic and ginger and chop finely. Wash coriander, shake dry, pluck off leaves and chop coarsely.
Heat 2 tablespoons of oil. Briefly sauté the spring onions, garlic and ginger in it and remove from the heat. Stir in soy sauce, 3 tbsp water, 1 tbsp oil, 2-3 tsp sugar and coriander. Season with pepper.