Peel and de-vein the prawns,then halve lengthways.

Thinly slice white ends of spring onions into rounds and reserve. Chop green ends of onions and combine with oil in a small saucepan. Cook over low heat for 10 minutes to infuse. Cool to room temperature,then strain.

Dry-roast Sichuan peppercorns in a small frypan for 1-2 minutes,until fragrant. Finely grind using a mortar and pestle.

Finely chop 2 chillies. Using a mortar and pestle,pound chopped chillies with the Sichuan pepper,ginger,¼ cup of coriander leaf,coriander stem,sugar and salt to a fine paste. Add vinegar and green onion oil,mix to combine and set aside.

Thinly slice remaining chilli. Combine in a bowl with prawns and sliced spring onions and remaining coriander. Drizzle with dressing,toss well to coat,arrange on a serving plate and serve immediately.