Chow-chow chutney

This is a "Madhava" dish which is very popular in Bangalore. Like many other dishes in the Madhava cruisine, the chutney is multipurpose- you can have it with rice (and ghee) or with rotis. My mother has it with dosas, and I think it tastes best with curds.

1 medium chow-chow, deseeded, peeled and chopped
1 tsp mustard seeds/ rai
2 tbsp chana dal
1 tbsp urad dal
1-2 red chillies (according to taste)
1 marble sized ball tamarind soaked in a little warm water
1 tsp oil
salt to taste

Heat oil in a kadhai, add mustard seeds. When the spluttering dies down, add red chillies and the dals, and fry on low heat till well browned.
Add chopped vegetables, and fry on low heat for 2 - 3 minutes.
Add tamarind juice, sprinkle water, cover the kadhai and let it cook in its own steam till soft.
Remove from flame and let it cool.
Pour into a mixer, add salt to taste, and grind till all the vegetables are pureed and the dals are coarsely ground.
Tastes best when cold (unless you are having it with rice).

Notes-
- the recipe calls for 2 red chilies, but put more or less according to taste, and the relative hotness of the chilli
- tamarind can be replaced with lemon juice and/ or vinegar, but considering most of the taste comes from the roasted dal, the chillis and the tamarind, think before replacing
- some people also add coriander to the chutney before grinding- it is not a part of the original recipe, and I do not do it
- some people temper the chutney with mustard seeds, curry leaves and channa dal- I personally prefer it otherwise