Mutton kosha is an iconic Bengali delicacy. The word kosha is similar in meaning to bhuna, which involves slowly cooking a gravy over low flame for a very long time to get a rich, dark-brown gravy and melt-in-the-mouth mutton pieces. It is worth pointing out that in Bengal, as well as in India, mutton is commonly used to refer to goat’s meat.

Mutton kosha (or kosha mangsho) can be served with luchi, porota or polao. It tastes great even with plain rice.

One of the most famous shops selling this style of mutton kosha is Golbari at the Shyambazar crossing in Calcutta. While we are not certain that our version is exactly like Golbari’s, we can assure you it certainly tastes very good.

ℹ️ Why we don't use complex marinades anymore, but you can if you want

Updated: Nov 10, 2023

These days we marinate meat with just salt, while skipping additional flavourings such as onion, garlic, spices, yoghurt, etc. We add salt to the meat (usually about 1–1.5% by weight of the meat), and spread out the meat on a tray in the fridge overnight, or up to a day. We don't add other flavourings to the marinade because it has been found that larger molecules such as those of onion, garlic, etc. do not penetrate meat more than about 3mm from the surface. Only salt can penetrate further. You can continue to marinate if you want to, there is no harm in doing it. Marinating is just an additional step that requires time and planning, but which has little to no effect, especially in slow-cooked dishes.

The raw smell of garlic, onion, etc. from the marinade can take additional time to get rid of considering that the meat is added much later in the cooking process, when the rest of the onion, garlic, ginger and spices are already cooked. Yoghurt and other acids were earlier believed to tenderise meat but because none of these molecules can penetrate very far into animal muscles, the tenderising effect, if any, is minimal and limited to the surface.

Our three mutton curries

Even though everyone has their go-to mutton curry recipe (we have four on our channel!), what matters from the perspective of the end result is not so much the proportion between the ingredients, but how they are cooked.

For example, the degree to which you braise the onions, whether you slow-cook open pot or pressure-cook, and so on, impact the flavour, texture, viscosity and mouth-feel of the final sauce. And the good part is that all of these are perfectly acceptable ways of cooking mutton, because a mutton ’curry' is a spectrum—sometimes one in in the mood for a comforting, thin, stew-like, piping-hot mangsher jhol, and sometimes for a rich, decadent caramelised kosha mangsho.

Over various recipes we've published over the years, we can demonstrate how if you tweak your cooking method slightly, you can get the result you are going for in terms of flavour and texture of the sauce.

Mutton kosha

We first posted this recipe in 2017, and it has since remained one of the most watched videos on our channel (7M views and counting!). In fact, chances are, since you're on this page, this is not your first time here—countless viewers around the world make kosha mangsho following this recipe every week!

Kosha mangsho (or mutton kosha) is not a home-style recipe. It is a Calcutta "cabin" restaurant specialty (think Golbari, Dikhusha, or the now-closed-down North Pole). It characterised by a dark, deep, caramely, nutty flavoured, thick sauce that barely coats the fall-off-the-bone tender meat.

To achieve this kind of a rich sauce, this recipe uses a LOT of onions to the proportion of meat: 500g onions for 1 kg mutton. The onions are braised separately first until very well caramelised, and then the mutton is introduced, and everything braised together for close to a total of 3 hours (!!) to develop the flavours further and cook the meat. Water is added only a little at a time to aid in the braising process.

This is not a mutton curry you put on the back-burner. It needs constant stirring and attention, and the cook is always straddling the fine line between "controlled browning" of the sauce (that is, pushing and deepening the flavours further until just short of burning), and going too far and ending up with a burnt, bitter mutton kosha!

Slow-cooked mutton curry

A year after our mutton kosha video, in 2018 we posted a recipe for a "Sunday" Bengali-style mutton curry (or pathar jhol). In this, we reduced the onions to 400g, braised the onions and meat until they were well-browned, added water for the sauce and simmered it on low heat, covered, until the mutton was completely cooked.

Cooking mutton in a kadai or pot takes long: up to 2 hours depending on the quality of the mutton. But this time-consuming method of slow-cooking the meat (instead of using a pressure cooker) gives us more control over how far to cook the mutton, so that it is neither too soft nor too chewy.

Additionally, this method yields a sauce with more body. This is because the process of conversion of collagen (present in the connective tissue of the meat) into gelatin (which is responsible for the silky mouthfeel) is a factor of time. There is no way to hasten this process. Cooking the meat in the sauce for about 2 hours creates more gelatin, which leads to a more viscous sauce that coats the mouth while eating.

Pressure-cooker mutton curry

Our pressure-cooker mutton curry recipe, released in 2023, completes the transition from the thick, dark sauce that coats the meat in mutton kosha to a thin stew-like sauce. It is also at the opposite end of the flavour spectrum from mutton kosha, in that we don't brown or caramelise the onions that much. Instead, we sweat them very gently, on low heat, ensuring that they don't brown or turn birista-like, to keep the flavours light and fresh.

In this version of mutton curry, we dropped the amount of onions per kg further down to 250g; we also finished cooking the meat in a pressure cooker (for 15 minutes). Since this is not enough time to develop gelatin, the sauce remains runny, stew-like, hearty and delicious!

BONUS: Niramish mangsho

This is an interesting and unusual example of mutton curry cooked without any onions at all! The base of the sauce in "niramish" mangsho is formed entirely of ginger, spices and yoghurt, all cooked and emulsified in oil and ghee! This is a completely different category of mutton curry, one not cooked in homes or cooked regularly at any rate—these days more a novelty, or point of interest, than common practice.