Wash 20 small prawns and chop into fine slices.
Add 1 tbsp brown vinegar and 1 tsp white pepper powder to prawns and keep aside for 5 minutes.
Heat 2 tbsp oil in a pan and fry sliced prawns.
When prawns begin to change color, add 2 chopped scallions and lower the flame after 2 minutes.
In a bowl, beat 4 eggs with some water and also add 1 tsp corn flour, salt to taste and 1/2 tsp black pepper powder.
Spread the eggs mix on prawns and fry on a medium flame. Change sides to cook thoroughly.
Cut into four pieces to serve.
Cook together 1 cup chicken stock, 1 tsp corn flour and 1 tbsp oyster sauce.
Pour the sauce over omelet when sauce is thicker.
Top with sliced spring onion and serve.