1. Heat oil in a pan over a medium-high heat, fry mustard, fennel, coriander, cumin seeds until they start to pop, add onions and sauté until onions are soft.
2. Now add ginger and sambal, cook for 2 minutes, add remaining dry spices and ½ the coconut thread and cook out for another minute.
3. Add fish stock, coconut cream, fish sauce, sugar, ½ fresh lime juice/zest, fresh chilli and a pinch of white pepper.
4. Heat and bring to a rolling boil, add the diced fish and curry leaves, simmer for another 5-10 minutes until fish is cooked.
5. Serve with basmati rice, remaining fresh lime & coconut thread, crispy shallots and coriander leaves.