Heat Olive Oil in a large frying pan and add the onion, mustard seeds, cumin seeds, curry leaves and crushed garlic. Cook until the onion is soft, 5-8 minutes.
Add tomatoes to a blender and liquidise. Set aside.
Once the onions are softened add the chilli powder, ground coriander, ground cumin. Add in the liquidised tomatoes and 1 teaspoon of salt. Cook for 20 minutes.
While the tomato gravy is cooking add in the tomato paste.
Add the fish and cook for 5 minutes or until the fish is fully cooked. It took me about 10 minutes.
In a saucepan combine the polenta and water over medium heat. Add in the remaining ½ teaspoon salt and stir. Cooked for 10-15 minutes, stirring every now again until the water has completely absorbed, and the polenta is cooked. You want it soft not stiff
Mould the polenta in the middle of a plate (it’s about half a cup cooked per person). Make a well in the middle of the polenta and fill it with fish curry.
Squeeze fresh lemon juice over the curry and garnish with fresh parsley or coriander.