In a food processor, turn onion, garlic, candlenut, cardamom, and water, into fine paste
Dump paste into a pot, with the rest of the ingredients, pour in water
Cook covered on low-medium heat, stirring occasionally, until broth is lessen (30 mins)
Uncover, add in another 500 ml water, continue cooking, covered, for another 30 mins
Uncover again, pour in another 500 ml, continue cooking until gravy is thickening, lamb is tender