Place curry powder, garlic, ginger, almonds, onions and water into a blender or food processor and mix to a puree.
Heat ghee and brown lamb in batches.
Add puree to pan and cook, stirring, for 2-3 minutes.
Return lamb to pan with remaining ingredients, cover and simmer for 40 minutes, until lamb is tender and sauce smooth.
Serve Rogan Josh with rice, fruit chutney and pappadams.