[To prepare sambal belacan:] Toast the shrimp paste over an open flame or stir-fry it in a frying pan. Pound the chillies with the toasted shrimp paste with a mortar and pestle until the desired consistency.
[To cook asam prawns and fish:] In separate bowls, marinate the prawns and mackerel with tamarind pulp, salt, sugar and dark soy sauce. Set aside in the refrigerator for 2 hours.
Heat oil in wok or frying pan over medium to low heat. Separately, add the prawns or mackerel together with its marinade. Fry until dry and aromatic. Dish out and set aside.
[To wrap nasi lemak:] Scoop the nasi lemak onto the middle of a piece of banana leaf. Add an asam prawn, a piece of asam fish, a tablespoon of sambal belacan and a slice of cucumber. Fold banana leaf on both sides and tuck ends in to a form of pyramid-shaped parcel.