Step 1

If using whole coriander and cardamom, grind them finely. Remove the black seeds from the cardamom pod and discard the pod. It's easiest to grind the seeds in a mortar and pestle with a pinch of salt to provide some friction. Leave the cumin seeds whole.

Step 2

Heat a pan over a medium heat and add the olive oil. Fry the cumin seeds for a couple of minutes, making sure that they don't burn. (If using ground cumin omit this stage and add the cumin along with the other spices.)

Step 3

Add the chopped onion, garlic, seasoning and remaining spices to the pan. Fry for 7-8 minutes until the onion softens and starts to turn brown.

Step 4

Add the diced marrow, along with a couple of tablespoons of water. Mix, and cover the pan. Cook over a low heat for 20 minutes. Check frequently to ensure the curry doesn't stick or burn on the bottom of the pan. Add a splash more water if necessary. When cooked the marrow should be soft to the point of a knife.