In a heavy bottom pan over medium-high heat, foam out the butter
Add all the whole spices, once they are aromatic and energetic, add the onions, and 1 tsp salt.
Cook the onions until softened and translucent
Add the ginger and garlic, cook until they start to take color and are fragrent
Add the chili powder and 1/2 cup of water, simmer to reduce, looking for a thick paste
Add the lamb and marinade
Stir well to cover the meat with the paste.
Stir and cook until the lamb has softened.
Add water to cover, and add the rum
Cover and reduce heat to low
Cook until the lamb is soft and breaks down when squeezed.
Remove from heat
Stir in the fresh corriander
Taste, Season, and balance flavor