FOR THE STOCK:

300g prawns, shelled and deveined (reserve shells and heads)

1 tbsp cooking oil

500ml water

FOR THE SPICE PASTE:

4 fresh red chillies, stemmed

4 dried red chillies, stemmed and seeded

8 shallots, peeled

1 tsp belacan, toasted

FOR THE MASAK LEMAK:

2 tbsp cooking oil

3 pieces asam keping

400g sweet potatoes, peeled and cut into 1″ cubes

250ml thick coconut milk

400g young sweet potato leaves

1. Heat 1 tbsp cooking oil in a wok over high heat until shimmering. Add the prawn shells and heads and fry until aromatic, about 5 minutes. Pour in 500ml water. Boil for 20-30 minutes.
2. While the stock is boiling, prepare spice paste. Using a mortar and pestle, food processor, or blender, grind the spice paste ingredients until fairly smooth. If using a blender, add a splash of water to help the ingredients move along. Scrape out the spice paste into a bowl and set aside.
3. When the stock has finished boiling, turn off the heat and let cool for a few minutes. Strain the stock into a measuring bowl. Top up the stock with extra water so the liquid amounts to 500ml. Set aside.
4. Wipe out the wok with clean kitchen paper towels. Heat 2 tbsp cooking oil over medium heat. When the oil begins to shimmer, add the spice paste. Saute the paste until fragrant, about 5-7 minutes. Add the trimmed prawns and fry until they turn pink, about 3-5 minutes.
5. Pour in the prepared prawn stock and stir well. When the stock comes to a boil, add the sweet potato cubes. Turn the heat down to medium-low and simmer until the sweet potatoes are cooked but still a little firm, about 10-12 minutes.
6. Add the coconut milk and stir everything together gently. When the gravy comes back to a boil, add the sweet potato leaves and turn the heat off immediately. Remove the wok from the heat source. Stir the leaves gently into the gravy.
7. Turn the dish out into a serving bowl. Serve warm with hot white rice.