Heat one tbsp of the oil in a casserole pot over a medium-high heat. Season the beef and fry in the pot for 5-8 mins, turning with a pair of tongs half way until evenly browned. Set aside on a plate.
Heat the remaining oil and butter in the pan and add the onions. Fry gently for 15 mins or until golden brown and caramelised. Add the garlic, ginger, chilli, turmeric, ground coriander and cardamom and fry for two mins. Tip in the tomatoes, stock and sugar and bring to the simmer.
Add the beef, put a lid on top of the curry and cook over a low heat for 1 ½ – 2 hrs or until the meat is tender and falling apart. Remove the lid for the last 20 minutes of cooking.
Stir through the garam masala and cream (if using) and season to taste. Scatter over the coriander and serve with naan breads or rice.
