Heat 2 tbsp of cooking oil in a heavy-bottomed pan over medium heat.

Add the cumin seeds and let them sizzle for a moment until fragrant.

Add the finely chopped onions and sauté until they turn golden brown.

Stir in the minced garlic and grated ginger. Sauté for another 2 minutes.

Add the tomato puree, coriander powder, turmeric powder, red chili powder, and a pinch of salt. Cook this masala mixture until the oil starts to separate from it. This may take about 8-10 minutes.

Add the bite-sized lamb pieces and cook until they are well-sealed and turn brown on all sides. This should take around 5-7 minutes.

Pour in about 1 cup of water and mix well. Cover the pan and let the lamb cook on low heat for about 45 minutes to an hour, or until it becomes tender. Stir occasionally and add more water if needed.

Once the lamb is tender and the gravy has thickened, add the slit green chilies, garam masala, ground cumin, ground coriander, cinnamon powder, and cardamom powder. Adjust salt according to taste. Cook for an additional 5-7 minutes.

The lamb bhuna should have a thick, rich gravy coating the meat. If it's too thick, you can add a splash of water to achieve the desired consistency.

Garnish with chopped fresh coriander leaves.

Serve the delicious Lamb Bhuna with naan, roti, or steamed rice.