Kosu Xaak di Maas
A traditional Assamese fish curry where tender pieces of fish are simmered in a flavorful gravy with earthy colocasia (taro) leaves. This rustic dish, pungent with mustard oil, is a staple in Assamese homes and a true taste of the region.
For 4 servings
Marinate the Fish
- Clean the fish steaks thoroughly under running water.
- In a mixing bowl, combine the fish steaks with 1/2 tsp of turmeric powder and 1/2 tsp of salt.
- Gently rub the spices all over the fish pieces. Let it marinate for 15 minutes.
Shallow Fry the Fish
- Heat the mustard oil in a kadai or heavy-bottomed pan over medium-high heat until it is fragrant and just begins to smoke.
- Carefully slide the marinated fish steaks into the hot oil. Be cautious of splattering.
- Fry for 2-3 minutes on each side until they turn a light golden brown. Do not overcook them.
- Remove the fried fish from the pan and set aside on a plate.
Prepare the Gravy Base
- In the same oil, reduce the heat to medium and add the panch phoron. Let it splutter for about 30 seconds.
- Add the finely chopped onion and sauté for 5-6 minutes until it becomes soft and translucent.
- Add the ginger paste and garlic paste. Cook for another 1-2 minutes until the raw aroma disappears.
- Stir in the chopped tomato, the remaining 1/2 tsp of turmeric powder, and 1 tsp of salt. Cook for 4-5 minutes, stirring occasionally, until the tomatoes break down and oil begins to separate from the masala.
Cook the Colocasia Leaves
- Add the chopped colocasia leaves (kosu xaak) and slit green chilies to the pan.
- Mix well to coat the leaves thoroughly with the masala.
- Cover the pan with a lid and cook on low heat for 10-12 minutes. The leaves will wilt completely and become very tender. This step is crucial to prevent any throat irritation.
Simmer the Curry
- Pour in 2 cups of warm water and stir everything together. Bring the gravy to a gentle boil.
- Carefully place the fried fish pieces back into the pan, ensuring they are submerged in the gravy.
- Reduce the heat to low, cover the pan, and let the curry simmer for 5-7 minutes. This allows the fish to absorb the flavors.
- Turn off the heat. If using, stir in the lemon juice. Check for seasoning and add more salt if needed.
Rest and Serve
- Let the curry rest for 5 minutes before serving.
- Serve hot with a side of plain steamed rice for an authentic Assamese meal.
What to keep in mind.
5 tips from the recipe — small details that make a real difference to the final dish.
- 1Ensure colocasia leaves are cooked until completely tender to neutralize the compounds that can cause throat itchiness.
- 2Using mustard oil is key to achieving the authentic, pungent flavor of this Assamese dish. Heat it until it's slightly smoking to mellow its raw pungency.
- 3Do not over-fry the fish initially; a light golden crust is sufficient as it will cook further in the gravy.
- 4If you still feel a slight itch from the leaves, adding more lemon juice or a small piece of tamarind can help.
- 5For a richer gravy, you can add a paste of 1 tsp of poppy seeds (posto) along with the ginger-garlic paste.
Adapt it for your goals.
Fish Variety
You can use other freshwater fish like Catla, Ari, or even small whole fish instead of Rohu steaks.
Add VegetablesAdd Vegetables
Incorporate cubed potatoes or elephant foot yam (Ool) for a heartier curry. Add them after sautéing the onions and cook until partially tender before adding the leaves.
Souring AgentSouring Agent
Replace lemon juice with tamarind pulp or dried mangosteen (Thekera) for a different, more complex sour flavor profile.
With LentilsWith Lentils
A popular variation involves adding a handful of soaked black gram (mati maah) along with the colocasia leaves for added texture and protein.
Why this is on our healthy list.
Heart-Healthy
The Rohu fish is rich in Omega-3 fatty acids, which are known to reduce inflammation, lower blood pressure, and decrease the risk of heart disease.
Rich in Vitamins and Minerals
Colocasia leaves are an excellent source of Vitamin A and Vitamin C, which are crucial for vision, immune function, and skin health. They also provide essential minerals like potassium and iron.
Anti-inflammatory Properties
Turmeric contains curcumin, a powerful compound with anti-inflammatory and antioxidant effects. Mustard oil also possesses anti-inflammatory properties that contribute to overall wellness.
Boosts Immunity
The combination of garlic, ginger, and Vitamin C from the colocasia leaves and lemon juice helps to strengthen the immune system and fight off infections.
Frequently asked questions
Kosu Xaak are the leaves and tender stems of the Colocasia plant, also known as taro leaves. They have an earthy flavor and are a popular green vegetable in Assamese and other regional Indian cuisines.