Methods

1. Heat half the vegetable oil in a frying pan over a medium heat.  Add the coriander, fenugreek and fennel seeds and chopped red chillies.  Saute for a couple of minutes.  When the chillies have softened slightly, add the sliced onion.  Fry, stirring constantly, for about 5 minutes, until the onion is softened.  Set aside and allow to cool.
2. Puree the cooled spice mixture in a blender or a food processor with the tamarind pulp, adding a little water to loosen the mixture, if necessary.  Set aside.
3. In another frying pan, heat the remaining 2 tablespoons of vegetable oil.  Add the mustard seeds and cook until they pop, then stir in the curry leaves, green chillies, garlic and turmeric.  Mix in the spice puree and stir well.  Pour in 50ml water to make a sauce consistency, season with a little salt to taste, then add the sugar.  Bring the mixture to a simmer for 5 minutes.
4. Add the fish steaks to the frying pan and cook for a further 8 - 10 minutes over a medium heat until the fish is cooked to your liking.  Transfer to warmed serving plates and serve with pappadums or steamed plain rice.