Kosha mangsho means mutton that has been 'koshano' – stirred and seared slowly in its own masala until the oil separates and the meat turns deep brown. Kolkata's Golbari, a small eatery in Shyambazar, made it famous, and in many Bengali homes it is still the centrepiece of a Sunday lunch or a festive meal after Durga Puja.
The gravy is thick, almost dry, and dark from long bhuna rather than from food colour. Mustard oil, whole garam masala, a touch of sugar to caramelise the onions, and plenty of ginger and garlic give it a rich, slightly sweet and pungent character. Potatoes are often added for those who like them, and the dish tastes even better the next day.
At a glance
| Region | West Bengal |
|---|---|
| Cuisine | Bengali |
| Diet | Non-vegetarian |
| Course | Main course |
| Prep time | 20 minutes |
| Cook time | 105 minutes |
| Total time | 125 minutes |
| Serves | 4 |
| Spice level | Medium |
| Difficulty | Medium |
| Gluten-free | Yes |
| Key ingredients | mutton / onion / yogurt / mustard oil |
Ingredients
For the marinade
- 1 kg mutton (curry cut, with bone)
- 1/2 cup thick curd
- 1 tbsp ginger paste
- 1 tbsp garlic paste
- 1 tsp turmeric powder
- 2 tsp Kashmiri red chilli powder
- 2 tbsp mustard oil
- 1 tsp salt
For cooking
- 5 tbsp mustard oil
- 2 bay leaves
- 4 green cardamoms
- 4 cloves
- 2 inch cinnamon stick
- 1 tsp sugar
- 4 large onions, finely sliced
- 2 medium potatoes, halved (optional)
- 1 tsp cumin powder
- 1 tsp coriander powder
- 4 green chillies, slit
- 1 tsp garam masala powder
- 1 tbsp ghee
- Salt to taste
Method
- Mix the mutton with all the marinade ingredients and refrigerate for at least 4 hours, or overnight.
- If using potatoes, rub them with salt and turmeric and fry in 1 tbsp mustard oil until golden on all sides. Set aside.
- Heat the remaining mustard oil in a heavy pot until smoking, then lower to medium. Add bay leaves, cardamom, cloves and cinnamon, then the sugar. Let the sugar melt and caramelise for 20-30 seconds.
- Add the sliced onions and fry on medium heat for 15-18 minutes, stirring often, until they are deep golden brown.
- Add the marinated mutton with all the marinade. Raise the heat to high for 5 minutes, stirring constantly, then lower to medium-low.
- Add cumin powder, coriander powder and green chillies. Cover and cook, opening every 5-7 minutes to stir and scrape the bottom, for about 45 minutes. The meat releases its own water; add 2-3 tbsp hot water only if it sticks.
- Once the masala turns dark brown and the oil floats at the edges, add the fried potatoes and 1/2 cup hot water. Cover and cook on low for another 30-40 minutes until the mutton is tender and the potatoes are cooked through.
- Uncover and keep stirring on medium heat for 5 minutes until the gravy is thick and clinging. Finish with garam masala and ghee, rest for 10 minutes before serving.
Tips
- Use meat from the shoulder or a mix with some fat and bone – lean leg pieces turn dry in the long bhuna.
- To save time, pressure cook after step 6 for 3-4 whistles, then open and dry off the gravy on high heat.
- The colour should come from patient browning of onions and meat; resist adding more chilli powder to darken it.
Serve with
Luchi, basanti pulao or plain steamed rice, with sliced onion and green chilli.