Wash Fish chunks thoroughly; preferably under running water and marinade with Salt and Turmeric Powder.Peel and Cut Potatoes into four equal halves and marinate the potato chunks with Salt and Turmeric Powder as well.Cut Cauliflower into medium sized florets and apply salt and Turmeric Powder.Finely slice Onion.Now heat Mustard Oil in a wok.Deep fry fish chunks on medium heat till the fish chunks turn golden brown.Use the remaining oil to fry Potato chunks, until those turn golden and almost â…” cooked.fry Cauliflower florets until those turn golden brown in color.There should be around 1 Tbsp. of oil in the wok, and temper that with Whole Cumin Seed and Green Cardamom.Add the sliced onion along with green chili and cook until the onion turned into a translucent texture.Now add Tomato puree and cook until the raw aroma of tomato is goneNow add ginger and garlic paste and cook till the mixture release oil.Add little water give a thorough mix and add Cumin Powder, Coriander Powder, Turmeric Powder, Chili Powder, Sugar, and Salt. And cook for five minutes and stir continuously.Add little water in between.Now add 3 Cups of water and bring the mixture to boil.Add fried Potatoes and cook by covering the pan with a lid for 7-8 minutes on low flameCook till the potatoes are softened.Add Fried Fish chunks and fried cauliflower and cook for five more minutes in low flame.Finish the dish with Bengali Garam Masala and serve with hot steamed rice