Cut the prawns in half, removing the vein and picking out the prawn tomalley and placing it into a small mixing bowl.
The shell should be intact.
Add 1 tablespoon of annatto oil, pinch of pepper & 1 tablespoon of fish sauce to the bowl & mix
well. Set aside.
In another mixing bowl, add 1 cup of water, 1 tbsp annatto oil, 1 tbsp sugar and 2 tbsp fish sauce. Stir and set aside.
In a hot saucepan, add oil, half the garlic then the water spinach. Stir-fry the water spinach for 1 minute.
Add the oyster sauce mixture and stir-fry for another 1 minute. Set aside.
In a hot saucepan, add oil, remaining garlic & red shallots. Sauté for 1 minute or until fragrant.
Sear the prawns for 1 minute on each side then remove and keep warm.
In the same pan, add the seasoned annatto water, stir then turn the heat to high.
Add the prawn tomalley and stir again and simmer for 4 minutes until slightly thickened.
Now return the prawns to the pan and cook for a further 3 minutes or until cooked.
Taste the sauce and season accordingly, adding more salt and pepper if needed.
Transfer water spinach to a plate, place 2 prawn halves on top of the water spinach. Scoop a generous amount of sauce over the prawn and garnish with spring onion, coriander chilli & edible flowers.