Hot and Sour Fish Bengali style fish curry

Sauce: Lightly grind the mustard seeds in a mortar and pestle then set aside. It’s important not to grind the seeds too vigorously as they will become bitter.

Put the tomatoes, chillis, shallot, garlic and turmeric in a food processor and blend to a coarse paste.

To cook: Put the flour in a shallow dish and season with salt. Dust the fish in the flour, shaking off the excess.

Heat the oil in a large sauté pan and cook the fish until just cooked through and golden. Don’t have the pan too hot or the flour will catch and burn. Remove to a plate, cover and keep warm.

Add the mustard and cumin seeds and the bay leaves to the same sauté pan and sizzle for a few seconds. Add the tomato mixture and cook, stirring constantly, until the paste is fragrant and all the liquid has evaporated, forming a thick paste. Add the whole chillis, lemon juice and water, season with salt and simmer for 5 minutes or until the sauce has reduced by half. Add 1 teaspoon of palm sugar, taste and add the remaining sugar if needed. The sauce should still taste a little sour. Add the fish and turn to coat in the sauce. 

Pantry Note: 
Palm sugar: also known as Gur, Jaggery or Gula Melaka. Derived from several different palm trees, including the palmyra and coconut palms. The sap of the palm is boiled down and the result can be either similar to a thick honey, a soft paste or a hard cake which is then grated or shaved. These come in different shapes and sizes and the colour can vary from pale to dark. The flavour is quite caramelly and can be substituted with equal parts of brown sugar and maple syrup. Available from Asian supermarkets.