Put the potatoes in a pan of salted water, bring to the boil and cook for 10 mins, until just tender. Drain and set aside.

Drizzle the oil into the pan and fry the potatoes for 3-4 mins over a medium-high heat until lightly golden all over. Remove from the pan and set aside.

Stir in the onion, cardamom pods, bay, cinnamon stick, cumin seeds and kalonji (nigella) seeds. Fry for 6-8 mins until golden.

Stir in the chopped tomato, ginger and garlic paste, fenugreek, chilli powder, turmeric, ground coriander and cumin. Cook for 1-2 mins until the tomato softens.

Mix the gram flour and Greek yogurt together until smooth, then stir into the masala mixture. Pour in 100ml water, simmer for 1 min, then stir in the potatoes to coat with the masala sauce. Cover and steam for 8-10 mins over a low heat. Sprinkle with more kalonji seeds, chopped coriander, garam masala and cashews to serve.