• 55 g (2 oz/¼ cup) whole black gram* (ulundu) (or store-bought skinned black gram)
• 285 g (10 oz/1½ cups) coarse semolina
• 1 teaspoon bicarbonate of soda
• ¼ teaspoon salt
• vegetable oil, for cooking

Soak the black gram in 250 ml (9 fl oz/1 cup) water for 8 hours (skinned black gram also needs to be soaked). Wash and drain. If using whole black gram, remove the outer skins by vigorously rubbing and squeezing them between your fingers and palms. Continue until most of the skins are removed (this will take about 1 hour). Discard the skins, retaining only the white bit of the black gram. Place the skinned black gram in a food processor with 185 ml (6 fl oz/¾ cup) water and process to form a thick but fine paste. Leave the paste in the processor.

Line a bamboo steamer with two layers of muslin or a piece of non-stick baking paper. Place the semolina in the steamer and cover with the lid. Fill a wok about one-third full with water and bring to the boil. Place the steamer in the wok, ensuring the bottom of the steamer isn’t touching the water, then reduce to a simmer and steam the semolina for 4 minutes.

Add the semolina and about 185 ml (6 fl oz/¾ cup) water to the gram paste, and process to combine (the consistency should be thick but runny). Transfer to a large bowl, cover with plastic wrap and a tea towel and leave to ferment in a warm place for 8 hours or overnight.

When fermented, dissolve the bicarbonate of soda in 1 tablespoon water and add to the semolina mixture along with the salt. Mix well. If needed, gradually add a little water (about 2 tablespoons). The consistency should be thick but still runny.

To cook the idli, lightly brush the idli moulds with oil, then spoon in the mixture, cover and steam for 10-15 minutes. To test if the idli are cooked, remove one with a spoon, hold it in the palm of your hand and with your other hand tap it lightly; if the idli bounces, it is ready. Remove the remaining idli from the moulds with a spoon. Serve hot with sambar and green coconut chutney.