In a pan, add 1 tbsp of oil, let the oil get hot and then add cut potatoes. Give potatoes shallow fry, then take out and keep aside.
Now in the same pan, add 1 tbsp of oil, and once oil is hot, add onions, garlic and ginger. Keep the heat low to medium. Fry till the raw smell fades away.
Add chopped tomatoes and turmeric powder and fry till tomato is not raw and crunchy.
Move all these contents and grind to a paste, and keep it aside.
In the same pan, now add 1 tbsp of oil. Once oil has heated add bayleaves, black cardamom, cinnamon and cloves.
Add cumin seeds and when the seeds crackle, add cumin powder. Now add red chilli powder as well as coriander powder. Keep stirring the pan constantly.
Now add the pureed onion, garlic, tomato in the pan and cook for 2 mins. Add 1.5 cup of water.
Once the water gets a bit of boil, add cut lamb pieces in the pan. Add more water if required and cover the pan.
After 30-35 mins lamb would get almost cooked. Check by taking a lamb piece out to see if its almost cooked. Now add the potatoes. Add more water if required to get desired consistency of the gravy.
Let this cook on medium heat for another 8-10 mins. Finally add garam masala and mix it. Let this cook for 2 mins.
Serve this hot lamb curry with rice or roti/ chapati.