Start by marinating the fish fillets. Rub turmeric and salt onto the fish fillets, ensuring they are evenly coated. Set aside for 15 minutes.
Make a masala paste with ingredients listed under 'Masala Paste'
Next, heat vegetable oil in a pan over medium heat. Add the sliced onion, ginger, and garlic juliennes and cook until onions turn golden brown, stirring occasionally. This will take approximately 4-5 minutes over medium heat.
Now, it's time to add the masala paste. Mix all ingredients well and cook for 2-3 minutes until the raw smell disappears. Also, add salt to taste.
Add approx. 200 - 250 ml water to make the curry. Mix well, add the chopped tomato and slit chillies and bring the curry to a boil.
Gently place the marinated fish fillets into the pan, submerging them in the curry. Let the fish cook in the gravy for 7-8 minutes or until it is cooked well and flakes easily with a fork.
Once the fish is cooked, turn off the heat. Serve hot with steamed rice or rotis for a complete meal. The combination of the fish and aromatic curry is simply irresistible.