This is an easy recipe. Your har lok will be delicious so long as the prawns are fresh and not overcooked. Frying prawns in the shell gives them an irresistible aroma. You'll drool before the dish is done. And you'll lick the plate clean after it's done.
In a wok or pan, fry prawns in very hot oil over high heat till 70-80% cooked, in batches if necessary to avoid overcrowding. Transfer to a plate.
1 tbsp corn oil
Drizzle water around the pan/wok. Swirl to deglaze. Add Worcestershire sauce mixture. Reduce sauce till slightly thickened. Taste and adjust seasoning if necessary.
2 tbsp water
Add prawns to sauce and toss till well coated and fully cooked. Sprinkle with a few drops of white sesame oil. Plate and serve.