Heat the oil in a kadhai or deep, heavy-based pan over medium heat, sprinkle over a little water, then add the asafoetida, cumin seeds, fenugreek seeds, and crushed and ground ginger and fry for a few seconds.
Add the cauliflower, season with salt, then add the chilli powder, garam masala, sugar, and turmeric and shake the pan, so that the masala is well mixed.
Add 2 tablespoons of water, reduce the heat to low, and cook for about 8-10 minutes, or until the cauliflower is cooked. Add the coriander and toss again.