Heat the oil in a saucepan and add the cassia, cloves and mustard seeds.
Once the seeds have popped, add the onion and carrot and cook until the onion is soft.
Add the ground coriander, ginger, garlic and chillies and stir well.
Stir in the turmeric and cumin, then add the tomatoes.
Season with salt, pepper and a pinch of sugar.
Add 250 ml water and bring to the boil.
Add the meatballs to the simmering sauce, one at a time.
Move the meatballs gently a couple of times during cooking to prevent sticking. Be careful not to break them up.
Simmer for 10 to 15 minutes until the meatballs are cooked through.
Stir in the cardamom seeds, yoghurt and coriander and serve with basmati rice.
Put one finely chopped onion, one slice of bread, and one egg into a bowl.
Add 500 g extra lean beef mince, one grated carrot, 10 ml beef stock powder and 10 ml poppy seeds and mix well.
Refrigerate until ready to use.
Just before cooking, roll the mixture into balls and coat each one in flour before adding them to the sauce.