Method

1. Rinse the chana dal and put in a large pot with the turmeric, whole onion and water (if you prefer a thick dal, use five cups/1.25 litres/44 fl oz of water). Bring to the boil over medium to high heat, stirring occasionally to prevent the peas from lumping.
2. Reduce the heat to low and simmer, partially covered, skimming occasionally, for about 35 minutes or until the peas are tender and break up under pressure from the back of a spoon.
3. Remove from the heat and discard the onion. Beat the mixture with a wooden spoon. If you prefer a coarse texture, purée half the mixture in a blender or food processor and mix it with the rest of the of the mixture.
4. Return the dal to the pot with the cloves, cinnamon stick, chillies, tomatoes and salt. Simmer for about 10 minutes, stirring now and then to prevent sticking.

FOR THE TADKA 

1. Heat the oil in a small frying pan and when very hot add the cumin seeds.
2. Fry the seeds for 10 seconds, or until dark brown.
3. Add the onions and fry for about 10 minutes, stirring constantly. This is an important step. Browning the onions is what will give the dal its magnificent aroma and flavour. First, the onions will steam, then they will gradually change to a deep caramel brown.
4. Add the ginger, chillies, garlic and curry leaves, if using (but they do ‘make’ the dish), and cook for a further five minutes.
5. Divide the dal between warm bowls, top with the tadka, and garnish with coriander and, if liked, extra curry leaves.