Cut the freshwater prawns into halves. Sprinkle lightly with a little salt and pepper. Parboil the prawns in boiling hot water until they turn red and are cooked. Dish out and set aside.
Loosen the wantan noodles and place on a steaming tray and steam over rapid boiling water for 2 minutes. Remove and cool. Loosen the noodles and deep-fry in batches in hot oil for 20-25 seconds until crispy and golden. Remove with a wire-mesh ladle and place on a serving dish. Arrange the prawns on top of the noodles.
Heat oil and sesame oil in a wok, fry garlic until lightly golden then add ginger. Add in the cooking wine and fry the garlic and ginger until fragrant. Add the Chinese cabbage, water and seasoning and bring to a simmering boil for 4-5 minutes.
Thicken the sauce then lower the flame and stir in the egg. Pour the sauce over the noodles and serve immediately.