Bruising cardamom pods simply means splitting them, do this by placing on flat surface and pressing down on them with flat side of a knife until the pod splits.
Combine lamb with both pastes in storage container or ziploc bag, coat lamb thoroughly in paste and refrigerate several hours or overnight. (preferably overnight).
Heat half the oil in a large saucepan, add onion and cardamom and stir until onion softens, add cumin and stir until fragrant. Add rice, stock, water and coconut milk, bring to boil and then reduce heat to a simmer, cook covered about 20-25 minutes until rice is just tender and liquid has absorbed.
Note: I have had times when I make this that all the liquid is gone and the rice is not quite cooked, just leave the lid on over the lowest heat you have on your stove, stir from time to time until done. Don't add more liquid it will just make rice go soggy.
While the rice is cooking, heat the other half of oil in a large frying pan. Add lamb with paste stir, put a lid on and cook until lamb is done stirring from time to time about 20 minutes.
In a medium bowl combine yogurt, onions and cucumber. This can be made ahead of time if desired.
To serve place rice on plate top with lamb pour some liquid from pan over and top with raita.