Heat up oil in Dutch oven and add onions. Cook until soft; they don't have to be caramelized.
Add lamb, carrots, Opah herbs, star anise, cinnamon stick, cloves, cumin and coriander powder, pepper and salt, half a cup of water and 2 tbs of lemon juice. Cover with lid and cook over low heat for 45 min.
Open lid and check for seasoning and tenderness of the lamb. If not soft enough, you can continue cooking it for another 10-15 minutes. If there's not enough gravy, add a few tablespoons of water to avoid burning. (Recipe Notes 2)
Once lamb is done, add equal amounts of rice and water, followed by cashews and fried shallots. Mix everything roughly.
Cover with lid and continue cooking over low heat until water has dried up and rice is fluffy and individually separated. Serve with a cucumber raita (See Recipe Notes 3).