In the garden in India, my grandmother used to grow beautiful small aubergines, and I picture them whenever I make this soup. Sambar originally comes from southern India, but is now enjoyed by people the world over because it is light and healthy but full of the most amazing flavours.
Rinse the tuvar dhal at least four times in hot water, using your fingertips to rub the oily coating away and check for small stones, then leave to soak in hot water for 15 minutes before draining.
Put the dhal in a large pan with 1.5 litres of boiling water (you can add one litre now and top up with the remainder while the dhal is cooking if your pan isn't big enough to take 1.5 litres all at once). Bring to the boil, then simmer over a medium heat for a couple of minutes until it starts to foam. Skim the froth from the surface, add the teaspoon of oil and simmer three-quarters covered for a further 28-30 minutes, stirring occasionally, until the dhal is cooked through (it should squash easily between your thumb and forefinger).
Add the tomatoes, bring the mixture back to the boil and simmer three-quarters covered again over a medium heat for 2-3 minutes, stirring every minute or so. Remove from the heat and blitz with a blender until the mixture has a really smooth texture.
Return the pan with the blended dhal-tomato mixture to a medium heat, stir in the aubergine and bottle gourd cubes along with the last 500ml of boiling water and leave to cook uncovered for 2-3 minutes. While it is cooking, crush the ginger with a pestle and mortar (or in a blender) to make a fine pulp.
Add the ginger, peas, salt, turmeric, chilli powder, sugar, garam masala and chopped coriander to the dhal mixture and stir through. Leave to simmer gently uncovered for 4-5 minutes while you prepare the tarka.
Heat the sunflower oil in a small pan over a medium heat for about 30 seconds, then add the cumin seeds. When they start to darken (after about 30 seconds), tip in the mustard seeds, and as soon as they start to pop, add the asafetida. Add the curry leaves (be careful, as they will sizzle and spit), then slowly and carefully pour in a ladleful of the lentil vegetable mixture, a little at a time - I do this at arm's length, as the hot tarka will spit. Stir through, then pour the contents of the small pan into the large pan containing the rest of the lentil mixture and stir again.
Bring the sambar to the boil and simmer for 10-12 minutes partially covered over a low heat, stirring occasionally. Remove from the heat, cover and leave to rest for 15 minutes to allow the flavours to develop.
Reheat to boiling before serving, making sure that you stir well, as some of the magic will be at the bottom of the pan. Any leftovers can be stored in an airtight container in the fridge for a couple of days, to be reheated with a little extra water and enjoyed as a speedy lunch or supper.
Notes: this recipe is vegan, wheat-free, onion and garlic-free, nut-free and healthy.
Recipe from Prashad At Home: Indian Cooking From Our Vegetarian Kitchen by Kaushy Patel, Salt Yard Books. Photography by Matt Russell.