Crispy rice crêpe with spiced potato (Masala dosa)

1. Soak the rice, and the urad dal with the fenugreek seeds, separately in cold water for 6 hours. Drain and grind each separately in a blender with a little water to a very smooth paste. Mix together, add salt and leave covered in a warm place for 10-12 hours (overnight) to ferment until risen and pleasantly sour-smelling.

2. For the filling, boil the potatoes in their skins until tender, peel and crush coarsely. Fry the mustard seeds in the oil, then add the curry leaves, chopped green chillies and thinly sliced onion and cook for 5 minutes until soft.

3. Add the turmeric, salt, potatoes and water and cook together for 3-4 minutes until soft and loose. Keep warm.

4. Thin the fermented batter with enough water to give a thick pancake batter consistency. Heat a large non-stick pan well, wipe it with oiled kitchen paper and pour a ladleful of batter into the centre.

5. With the bottom of the ladle, spread it thinly in quick spiral movements working outwards. Drizzle a few drops of oil around the edge and cook for 2-3 minutes until the underside is golden and crisp (no need to turn it).

6. Spoon some filling into the centre of the dosa, drizzle with a little ghee, roll up or fold in half and serve at once with coconut chutney and sambar.

Tip: South India's most famous dish; fermentation gives it its tangy flavour and crispness. In a cool kitchen fermentation can take longer: put the bowl in the switched-off oven with the light on. The first dosa is rarely perfect, so don't give up!