In a mixing bowl, mix the lamb meat with all the marinade ingredients, then cover and put in the fridge to marinate for 2-3 hours or overnight.
Make the curry
Soak the cashews in boiling water for 8-10 minutes, then put the cashews with water in the food processor and beat until smooth.
In a large pot, heat the butter over medium heat, add onions and cook until soft, then add the garlic, ginger, garam masala, cinnamon and turmeric. Cook for 1-2 minutes.
Add the lamb and all its marinade, cashew and water, bring to a boil, after that reduce the heat to low, cover and simmer for 1-2 hours until the lamb is tender.
Stir occasionally and top up with more water if needed.
Garnish with chopped parsley (optional) and serve.
Notes
The key to a more delicious Lamb Korma is good and fresh lamb meat. The quality of the meat matters most in this recipe hence buys the freshest you can find.
Marinade the lamb the night before you make the curry so that the spices will have had settled into the meat already making it more flavorful.
Recipe Variations
Use red onions instead of white onions for the more pungent flavor of your curry.
You may use vegetable oil instead of butter in cooking your curry.
You can add beef broth instead of water if you like.