Prep time 15 mins, cook 30 mins
Preheat oven to 100C. Rinse ikan bilis under cold water, drain, spread on an oven tray and roast until dry and crisp (8-10 minutes).
Preheat oil in a deep-fryer or deep-sided saucepan to 140C. Deep-fry ikan bilis in batches, stirring frequently, until crisp and golden (3-4 minutes). Drain on absorbent paper, set aside.
Add peanuts to oil and cook until golden and crisp (4-5 minutes), drain on absorbent paper and set aside.
Process onion and chilli in a food processor to a smooth paste. Heat extra oil in a frying pan over medium-high heat, add onion paste, stir occasionally until fragrant (4-5 minutes). Add ikan bilis, peanuts and sugar, season to taste with sea salt. Cook for another minute, cool to room temperature and serve.