Heat a pan and add grated coconut. Toast it by stirring continuously on low-medium flame till the coconut turns to a dark shade of brown. Switch the flame off and keep aside to cool down. Then, grind it into a paste using a food processor. This paste is called 'Kerisik'.
Blend and grind the Rempah ingredients in food processor till it turns into a paste-like consistency.
Heat oil in the pressure cooker, and add cinnamon, cloves, star anise and cardomom pods. Stir and add the Rempah. Saute till the raw smell of spices is no more there.
Then, add the lamb cubes and pounded lemongrass. Mix well.
Add coconut milk, tamarind paste and water. Stir to mix well and leave to simmer on low-medium flame till the meat starts getting cooked. (You know it when you notice a change in colour and texture of the meat.) Stir occasionally to ensure the mixture is blended and doesn't get burnt.
Throw in Kaffir lime leaves. Then, add palm sugar, salt and the Kerisik that was prepared and kept aside. Stir to mix well.
Close the pressure cooker. Cook on low flame for 10 whistles.
Switch the flame off, and release the steam.
Then, cook further with the lid off. You will see the coconut milk turning into oil.
Continue cooking, stirring at intervals, till the gravy becomes dark brown in colour, dries up and the meat is soft and tender.
Lamb Rendang is ready. Serve with plain rice.