For the curry:
For the tarka (tempering):
Portion the salmon into 2-inch-thick pieces and season lightly with salt and pepper
In a mortar and pestle, crush the shallots, garlic, and ginger into a coarse paste
Heat the coconut oil in a large pan over medium heat and add the shallot–ginger–garlic paste, cooking for 5–6 minutes until it starts to caramelise
Add the curry leaves, sauté briefly, then add the turmeric, Kashmiri chilli powder, and coriander powder, stirring to coat
Pour in the water and bring to a gentle simmer, cooking for about 8 minutes. Add green chili here.
Add the tamarind and coconut milk, then simmer gently for another 5–6 minutes. Add in the canned salmon if using.
Slide in the salmon pieces and move the curry gently by swirling the pan, avoiding turning the fish so they stay intact and the coconut milk doesn't split
Simmer for about 15 minutes until the fish is cooked through and the sauce is glossy with a rich orange colour
For the tarka, heat the coconut oil in a small pan and add the mustard seeds, letting them pop
Add the fennel seeds and fenugreek seeds, then the curry leaves, chopped shallots, and sweet paprika and cayenne pepper, sautéing until golden and fragrant
Pour the hot tarka immediately over the curry and stir gently if desired
Serve hot with rice
