Mix ground spices with lime juice to form a paste and marinate beef for one hour in the fridge.
Heat oil in a lidded wok and pop mustard seeds under a closed lid.
Add cumin, curry leaves, asafoetida, chillies, and ginger, then stir-fry for two minutes.
Stir in tomatoes and lime juice and cook until tomatoes break down.
Off the heat, stir in yoghurt, coriander, and cooked rice then season with salt.
Heat oil in a clean wok and stir-fry beef for 4 minutes until browned.
Remove beef and stir-fry ginger, garlic, and onions until softened.
Add peppers, spring onions, tomatoes, chillies, and chilli powder and stir-fry until softened.
Return beef and its juices to the wok and toss for one minute.
Stir through fresh coriander and serve over the yoghurt rice.