To begin, bring a large pot of water to a boil. Blanch the water spinach for 30 seconds until bright green. Remove and immediately place into a bowl of iced water to retain colour and crispness. Drain well and set aside for assembly.
Next, blanch the bean sprouts for 20 seconds, then transfer to iced water. Repeat the same process for cabbage and long beans, blanching each for about 1 minute until just tender yet crunchy. Drain all vegetables thoroughly before arranging.
In a dry pan over medium heat, lightly toast the roasted peanuts for 2 minutes to release their oils and deepen flavour. Stir constantly to avoid burning. Remove and let them cool slightly before blending.
Using a food processor or traditional pestle and mortar, blend toasted peanuts, red chillies, garlic, kencur, coconut sugar, and salt until a coarse paste forms. Traditional pestle and mortar enhance flavour but require more time and patience.
Pour in warm water gradually while blending to achieve a thick yet pourable sauce. Add lime juice and kaffir lime leaves, blending briefly to incorporate without losing fresh citrus aromas. Taste and adjust seasoning if needed.
On a large serving platter, neatly arrange blanched water spinach, bean sprouts, cabbage, long beans, and cucumber slices in separate sections for an attractive presentation.
Generously pour the peanut sauce over the arranged vegetables, ensuring each type gets coated lightly while keeping the presentation colourful and distinct.
If desired, prepare additional sides like steamed rice cakes (lontong) cut into bite sized cubes or krupuk (Indonesian crackers) for extra crunch alongside the salad.
Sprinkle extra kaffir lime leaves or thinly sliced chillies on top for an added burst of colour and fragrance before serving to guests.
To conclude, serve Pecel at room temperature with warm rice cakes and crackers on the side. This dish is best enjoyed immediately to retain the vegetables’ crispness and the sauce’s aromatic freshness.