cup toovar dal (see NOTE), well washed (100 millilitres)
cup raw white rice, washed and drained (175 millilitres)
cup whole milk yogurt (100 millilitres)
tsp baking powder
tsp peanut oil or raw sesame oil
tsp black mustard seeds
tsp sesame seeds
About 6 fresh or frozen curry leaves (see NOTE)
1. Seven to 12 hours before you wish to serve the dhokla, start soaking the dal and the rice: Wash dal and rice separately. Place the dal in a bowl and add water to cover by one inch. Place the rice in another bowl and add water to cover by one inch. Cover both bowls and set aside to soak overnight or for at least six hours.
2. Drain dal, measure out 1 cup (225 millilitres) dal, and place in the food processor. Drain rice, measure out 1 cup (225 millilitres), and transfer to the food processor. Add 1/4 cup (50 millilitres) water and process for about a minute, until well ground. Add the yogurt and process again until smooth. The batter should be thick but pourable.
3. Set aside while you organize your steaming arrangement (see equipment note) and bring the water to a boil. Lightly grease a seven-inch (18 centimetre) diameter round cake tin.
4. Add salt and baking soda to the batter and process briefly to mix well. Pour the batter into the pan to a depth of between ½ and 3/4 of an inch (about 1 ½ centimetres) (the depth of your thumbnail is a good measure); you may not use quite all the batter.
5. Use oven mitts to protect your hands and arms as you transfer the pan into the steamer. Bring the water to a vigorous boil, then lower heat slightly to maintain a strong boil. After five minutes, remove the lid and wipe the underside dry, then replace the lid. Continue cooking until the top of the dhokla is shiny and the sides are pulling away slightly from the pan, about 15 minutes total. The dhokla will rise and puff after about five minutes, but needs more time to cook through.
6. Use oven mitts to protect yourself from the steam when you remove the pan from the steamer. Set it aside for 10 minutes to set. Use a sharp knife to slice it into about 1/2-inch / 1-centimetre diameter diamonds or squares; if any crumb sticks to the knife as you slice, wipe it clean and lightly oil the blade before proceeding. Set the pan of sliced dhokla by your stovetop.
7. Heat the oil in a heavy skillet over medium-high heat. Add the mustard seeds, and when they start popping, add the sesame seeds; once the seeds have popped, about twenty seconds, toss in the curry leaves and remove from the heat. Pour the oil and flavourings over the dhokla.
8. You can leave it in the pan until you are ready to serve it. Dhokla can be made up to several hours ahead. We think its best made half an hour ahead, to give it time to gain flavour from the oil and for the texture to firm up as it cools to room temperature. Use a spatula to lift the squares out of the pan and onto a serving plate or else serve from the pan. Serve warm or at room temperature.