Wash florets in salted water. Cube potatoes, keep in water. Whisk the yogurt; purée the tomatoes.
Heat the mustard oil until it smokes, then cool it a little. Drain the veg; fry cauliflower + potato on high ~5–6 min, until ~90% cooked. Remove.
In the same oil, the cumin, cinnamon, black cardamom and bay leaves; add the onions and . Add the ginger-garlic and chopped green chillies; fry golden.
Lower heat. Stir in the turmeric, coriander, cumin powder, chili powder, black salt and besan. Add a splash of hot water; roast 4–5 min.
Add tomato purée, whisked yogurt, salt. Cook on high 12–15 min until the .
Stir in peas; cover; cook 6–8 min. Adjust with hot water — half-thick.
Return cauliflower + potato; cook a few minutes. Finish with garam masala, , chilli strips, ginger strips, coriander.