A rice and lentil pancake stuffed with a spicy potato filling, the masala dosa is a fabulous vegetarian street food dish from India. The rice and lentils for the batter have a long soaking and fermenting time, and the fermenting process can be somewhat unpredictable, especially in colder climes. So give yourself plenty of time for this recipe. If the batter has not risen after 12–15 hours at room temperature, it is acceptable to help it along with some yeast.
Note: you will need to begin this recipe the day before you want to eat, as the rice and lentils need to soak, then ferment overnight.
For the dosa batter, add the rice, urid dal, chana dal and fenugreek seeds to a bowl and cover with warm water. Leave to soak for 6–8 hours. Do not drain or rinse – you will wash away the wild yeasts and reduce your chances of a successful fermentation. Working in batches, grind the rice and pulses with enough of the soaking water to make a smooth, creamy batter. A high-powered smoothie maker is perfect as it will grind the batter really well, but a liquidiser or powerful food processor would also work. Pour the batches of batter into a large bowl and stir through the coriander and salt. Cover with cling film and leave at room temperature overnight. By the morning, the dosa batter should have risen and be bubbly on the surface. If nothing has happened, mix the yeast with the 2 tablespoons of warm water, then stir through the batter and leave for a further 1–2 hours at room temperature.
Alternatively, if there are promising signs of fermentation on first checking, leave for a few hours longer without adding yeast. If it’s brilliantly bubbly (well done!) you can now transfer the bowl to the fridge to halt fermentation until you are ready to cook – it will keep in the fridge for a few days. At this stage you may need to thin out the batter by whisking through a little cold water – it needs to be thick enough to coat the back of a spoon nicely, but thin enough to spread out to a pancake; the consistency of thick double cream is about right. To make the filling, add the potatoes to a pan of lightly salted boiling water and cook for 12–15 minutes until tender. Drain well and set aside.
Add the oil to a generous frying pan with the mustard seeds and curry leaves and set over a medium-high heat. Once the mustard seeds start to pop, stir through the onions and chillies and reduce the heat to a minimum. Allow the onions to cook slowly to a soft melting mass, stirring occasionally, for about 40 minutes. Stir through the garlic, ginger and turmeric and season with salt and pepper, frying for another couple of minutes. Tip in the cooked potatoes and add the butter, if using, to add richness. Stir well over a low heat for a few minutes, mashing the potato a little as you go. Keep the filling warm while you make the dosas .
Take a large frying pan and add a little oil. Set over a medium-high heat. Once the oil is hot, brush it all over the surface of the pan using a piece of scrunched-up kitchen paper. Pour a ladleful of batter into the centre and, using the underside of the ladle, quickly swirl it around to spread out the batter to a thin layer. Allow to cook for a minute or two, then test if it’s ready to turn by lifting an edge with a fish slice. It should be golden and crisp. Flip over carefully and cook the other side. Spoon a little potato filling on to one side and fold the other side over the top. Serve immediately while you make the rest of the dosas , or keep warm in a low oven (around 110°C/90°C Fan/Gas Mark ¼). Garnish with a little coriander and serve with the chutney of your choice.