In a bowl beat 2 eggs, 2 tbsp water and 2 tbsp flour. Pour in the egg mixture into a non-stick pan and fry the omelet .When the omelet sheet becomes firm keep it aside.
In a food processor chop together chicken minced, soft black mushrooms, green onions, ginger, and egg white, tomatoes without seeds, black pepper, and white pepper, salt and lemon juice.
Transfer the minced meat mixture in a bowl. Now spread the minced meat mixture evenly on the omelet and roll.
Pack it with aluminum foil and steam in a steamer for 12-15 minutes. Serve hot.