Kosha mangsho is one of those great Bengali inventions, that special occasion dish we all look forward to, especially during Pujo. It is one of my absolute favourite things to eat. A kosha mangsho, if made well, will have tender, melt-in-the-mouth meat with a rich, flavourful sauce clinging to it. Eating a good kosha mangsho is an experience that, honestly, cannot be properly put into words.

Although the word “mangsho” is the generic Bengali word for meat, Kosha mangsho is traditionally made using mutton, which in Bengal and all over India refers to goat meat, unlike in the West where it refers to the meat of a sheep that is more than two years old. The word “kosha”, also called “bhuna” elsewhere in India, refers to the process of slow-cooking the meat and spices over a low flame for a long period of time, during which the ingredients slowly interact in the pot to create a rich and complex array of flavours.

Kosha mangsho, therefore, falls in the category of slow-cooked meat dishes. There isn’t a dearth of such dishes around the world, from pork bellies to lamb shanks, beef cheeks to oxtails. These dishes employ tough cuts of meat cooked over long periods of time during which the tough collagen present in the meat breaks down into gelatin which thickens the sauce and lends it a luscious mouthfeel. Kosha mangsho takes things a step further by adding a number of aromatics and spices which heighten the flavour to another level.

The ingredients needed to make a kosha mangsho, apart from the mutton itself, which needs to be of good quality, are relatively simple. All you need are onions, ginger, garlic, chilli, yoghurt, salt, sugar, and the usual list of spices that are readily available in any average Indian and Bengali kitchen: whole bayleaf, cardamom, cinnamon and clove; and powdered chilli, turmeric, cumin and coriander. There is not one exotic ingredient in sight unlike in a biryani for example, which calls for special ingredients like rosewater, meetha attar or dried plums; things that largely define the dish’s flavour. Of course, you could add things like nutmeg and mace to a kosha mangsho for another dimension of flavour, but it is entirely optional. There is one ingredient, however, that isn’t optional, and plays a key role in making a kosha mangsho great, and that is time.

Apart from a long cooking time, you can obtain tender meat by marinating it in a mix of yoghurt, aromatics and spices before the cooking begins. Acids in the marinade helps break down proteins which tenderizes the meat, allowing the flavours to penetrate even before the cooking has started. A lot of Indian meat dishes begin with this step, and kosha mangsho is no exception. You could marinade the meat overnight; the longer you keep it, the better. With the marination sorted, it’s time to get cooking. I’ve followed the recipe by Bong Eats and the result was fabulous. If you want to give it a shot yourself, check out their detailed recipe here. https://www.bongeats.com/recipe/mutton-kosha

The actual cooking process starts with a progressive layering of flavours. Whole spices are added to mustard oil (the intense, pungent flavoured oil valued by Bengalis as much as Italians value their olive oil) followed by sliced onions, aromatics and powdered spices. The entire mix is cooked for around 30 minutes or so. This might sound like a ridiculously long period of time, but it is necessary for the onions to caramelize and soften, and for the multitude of flavours to meld. What you end up with is an intensely flavourful base. The marinated mutton is then added, along with some seasoning. The flavours in the spiced onion mixture and the marinade start to intermingle. And now begins what is essentially the first step in most slow-cooked meat dishes the world: browning the meat.

The flavour of a well-made kosha mangsho is like the sound of a symphony orchestra. There are layers to it, and one of the most important layers is the Maillard reaction. It is a chemical reaction involving amino acids and sugars that produces a set of complex aromatic molecules that impart a distinctive flavour to browned foods. It is the flavour of the sear of a steak, the crust of a brioche, the toastiness of a marshmallow. It is the reason why a browned chicken breast tastes better than one that is boiled. And prolonged, controlled browning is the secret to a good kosha mangsho. During browning, the Maillard reaction takes centre-stage as the proteins in the meat and the sugars in the caramelised onions and yoghurt start to interact, creating an amazing array of flavour compounds which gives kosha mangsho its identity.

Once the meat is properly browned, it is time to add the braising liquid. But unlike in a beouf bourgignon, where the beef stock and red wine are poured in at once and the pot covered and left to cook slowly for hours, the liquid in kosha mangsho is ideally added in stages. A little hot water is added at a time and the pan is covered; after some time when the water has dried up, the bottom is scraped and the brown bits are incorporated back into the mixture, and some more water is added. This process is repeated multiple times, and over time, the meat tenderises, and the curry develops a rich brown colour and a great depth of flavour.

Caramelisation and tenderization occur simultaneously, giving us beautifully browned meat that melts in our mouth. And having a balance of both is essential for the process. Add all the water at once and you’ll still get a good-tasting dish with beautifully tender meat, but the flavours won’t be as intense. Add very little water or leave it uncovered and you’ll get excellent browning but very tough and dry meat. This gradual, time consuming technique helps to achieve the perfect balance between browning and tenderness.

After the desirable level of flavour is achieved, some more water is added to create a gravy, and the dish is finished with some fresh green chillies and a dollop of ghee. Kosha mangsho is traditonally served with polao or with luchi/porota, but it is just as great with plain boiled rice. A good kosha mangsho is basically a must-have in the indulgent, meat-heavy lunch of Nabami during Durga Puja. Golbari in Shyambazar, North Calcutta is famous for its kosha mangsho, although patrons claim that the overall quality has deteriorated over time. Good quality meat, a handful of easily available ingredients and a lot of time: these are the three things you need to make a good kosha mangsho. There are a lot of mediocre versions out there, but when made well, it truly is a dish fit for the Gods.

Wishing all the readers of The Gourmet Glutton a very Happy Durga Puja!