In a high-sided pan, heat 2 tablespoons of the oil and fry the aubergine until it is soft, cooked through and golden on all sides (about 6 minutes). Transfer to a plate.

Fry the onion and cumin seeds in the remaining oil until softened and lightly browned. Add a pinch of salt and the curry powder. Remove a third of the onions and set aside. Add the chickpeas to the pan and mix thoroughly.

Measure the rice in a measuring jug, then rinse under cold water, drain, and add to the onion mixture. Mix thoroughly to coat the grains in the oil. Season really well, and add the lemon juice, then add water (double the rice measurement). Bring to the boil, stir once, then cover the pan with a tight-fitting lid and cook over a very low heat for 10 minutes, undisturbed.

Remove the lid and tip in the spinach. Cover again and let it stand for 1-2 minutes, off the heat, until the spinach has wilted. Add the aubergine and mix in gently. To serve, top the biryani with the yogurt and the reserved onions.