Heat a large casserole pan with two tablespoons of oil.
Fry the lamb shanks until sealed all over and set aside.
Toast the coriander seeds, cumin, turmeric, cinnamon, cardamom, and star anise in a dry pan until fragrant.
Grind the toasted spices into a fine powder.
Sauté the onion, garlic, chillies, ginger, and lemongrass in the remaining oil until soft.
Stir in the ground spices and bay leaf and fry for a few minutes.
Return the lamb shanks to the pan and stir to coat thoroughly in the spice mixture.
Add the tamarind paste and coconut milk, bring to a boil, then pour in 250ml of warm stock.
Simmer on high heat to reduce the liquid, then reduce to low and cook for 2.5 hours until thick.
Cook the rice in 365ml of salted water over low heat until the liquid evaporates.
Remove rice from heat, cover, and steam for 10 minutes.
Stir coriander leaves and lime juice through the cooked rice.
Serve the lamb shanks over the rice with the rendang sauce on top.