Cut the cauliflower in medium size florets. Boil water with salt and soak the florets for 3-4 minutes. Drain and set aside.
Dry roast the pickling spices in medium heat until nice aroma comes. Once cool, grind them to a powder.
In a kadai, heat oil and add mustard seeds, cumin seeds and asafoetida. When it splutters, add onion and fry till soft.
Add ginger-garlic paste and fry till raw smell goes. Add tomato puree, turmeric powder, coriander powder, spice powder, salt and mix well.
Cook in low-medium heat for about 5-7 minutes or till the masala is cooked and oil starts to separate.
Add the cauliflower florets and mix well. Cover and cook for 4-6 minutes or till the cauliflower florets are cooked.
Add yogurt and cook for another 1-2 minutes. Remove from heat and add lemon juice, coriander leaves and mix.