Cook rice in 600ml water for 45 minutes until a crust forms on the bottom.
Drizzle oil over rice crust and cook for 5 minutes until loose.
Break cooled rice crust into small pieces and set aside.
Butterfly the prawns by splitting them open lengthways while leaving them attached at the back.
Stir-fry ginger, garlic, and spring onions in smoking hot oil in a wok.
Add prawns and stir-fry until firm.
Add sauce ingredients, bring to boil, then stir in cornflour paste and sesame oil.
Chop celery stalks into 2.5cm sections after removing strings.
Stir-fry garlic, ginger, and celery in a very hot wok for one minute.
Add seasonings and 3-4 tablespoons of water, cooking until celery is just tender.
Garnish celery with spring onions and coriander then transfer to a platter.
Deep-fry rice cake pieces in very hot oil for 1-2 minutes until puffed and slightly brown.
Drain rice cakes on kitchen paper and transfer to a warm platter.
Pour hot prawn sauce over the hot rice cakes and serve immediately.