- Marinate fish in turmeric & salt, fry lightly in 2 Tbsp. oil and set aside.
- If using dried mangoes, soak in 2 cups hot water until water cools, drain, reserve water for gravy and blend soaked mangoes to a paste.
- Heat 4 Tbsp. oil over medium-high heat and sputter mustard seeds.
- Add green chilies to oil, stir-fry until skin blisters and turns grey.
- Remove chilies from oil and set aside.
- Add potatoes and Kashmiri mirch to pan, cover and cook over medium heat until potatoes are half-cooked.
- Add tomatoes and ginger paste and continue to cook until tomatoes break down.
- Heat reserved liquid in which mangoes were soaked and add to pan along with mango paste.
- If using raw mangoes, add the wedges along with 2 cups hot water.
- Return green chilies to pan, bring gravy to a boil, adjust salt to taste and add fish to gravy.
- Stir well, bring to a boil, cover and simmer gently over medium-low heat for 3 minutes.
- Garnish with mustard oil and cilantro.