This is a easy and common dish to do. Did my own version of this dish with the prawn given by mum in law some time ago.
about 500g Prawns
6 tbsp ketcup
1 tsp vinegar
11/2 tbsp sugar
6 tbsp water
1. Rinse and trim prawn. Cut slit at the back of prawn, devein and marinade prawn with sugar, salt and pepper for 15min.
2. Coat prawn with corn starch. Fry in hot oil for 1-2 min. Remove and set aside.
3. Pour sauce ingredients in wok, stir fry for a while, then pour prawn back into sauce, stir fry the prawn till sauce thicken and dried. Dish and serve.