Add 1 tablespoon sunflower oil to a large frying pan and warm on medium heat, then add and sauté 1 large onion. Once golden brown remove from the pan and set aside.
In a large saucepan mix together the 1 kg lamb , 475 ml buttermilk, 5 cloves, 4 green cardamoms, 1 tablespoon ground cumin , 1 tablespoon ground fennel , 2 whole green chillies, 1 teaspoon Kashmiri Red Chilli Paste, 1 teaspoon coarse sea salt.
Partially cover and simmer on a low heat till the meat is soft and tender (approx. 45 minutes-1 hour). Use tongs to remove the lamb from the liquid* to a colander and set aside to drain for a couple of minutes.
In a large skillet heat 4 tablespoons sunflower oil on medium-high heat till hot then reducing to medium-low and fry the lamb pieces in batches till browned all over, around 8 minutes in total (see notes below for roasting the lamb instead). Transfer the lamb to kitchen paper to drain the excess oil. Garnish with the browned onions and chopped 2 tablespoons cilantro.
Notes
Use leg of lamb leg or shoulder, cut into small pieces.Drain the lamb from the liquid before frying as any excess liquid will spit.If you prefer not to fry the lamb transfer it to a baking dish and roast on full heat for 5-10 minutes.*After simmering the lamb, strain and reserve the liquid to use as a tasty stock for pilau/rice.This recipe can be made ahead and reheated on a low heat before serving.Store leftovers in a closed container in the fridge for up to 4 days or in the freezer for up to a month.