This quantity will feed one or two people but there will be none left as it is a great recipe. We usually make 6X which leaves some leftovers - can be frozen. Also, like most curries, this is always better the next day when flavours have mixed.
Soak the dahls for 1 hour - not absolutely necessary, but softens them.
Heat 1/2 the ghee and fry the ginger gently for a couple of minutes, before it goes brown add the turmeric and the dahls.
Turn up the heat and stir fry for 5 minutes then cover with some of the water and cook over a medium heat until dahl is soft - about 15 minutes. Blend or mash it all into a paste, a bamix type thingy works well.
Heat the remaining ghee and fry the mustard seeds, cumin seeds, chillies, curry leaves and garlic until the mustard seeds start to pop. Rescue any that escape the pan as they taste yummy!. Add the eggplant and potato and fry for 5 minutes. The potato wasn't in the original recipe but adds some bulk, flavour and texture to the dish.
Add tomatoes, sugar, salt, garam masala, the mashed dahl and remaining water. Cover and cook until the vegies are all tender. You may need to add more water if it gets too thick - it is good when you can pour it, but it isn't too runny.
Cook it as slowly as you can as like most dahl recipes it has a tendency to stick to the bottom of the pan. If it doesn't burn, the layer on the bottom can be mixed in or scraped off and eaten as the cook's bonus.
We serve it with rice or just mop it up with warm chappatis or turkish bread.