Kathrikai Gotsu / Eggplant Gravy

The first time I had Kathrikai Gotsu was last year when I went to India. One day when my mil said let's make Gotsu with Pongal, I knew I was still new to Tamil cuisine, I kinda stared blindly, quite not sure what she was talking about...so then she showed me how to make it(I even had her spell it out to me!!), and apparently it is very easy.I can't believe I did not know such a dish existed. The funny thing is once I came back to Chicago, I found this gotsu everywhere .. at lunches, potlucks, dinners, you name it and there it was. So here is my dear amma's recipe .. and yes she is a fabulous cook... I can't wait to see my hubby's parents ...they are coming to CA in march.. very cool people.
As you can imagine other than the main measurements ...most are eyeballed so ...the eggplant quantity is what I use ... the rest of it is her measurements.
I like it a little thick feel free to add water until it reaches the consistency you prefer.

Ingredients:
Passi Parippu / Split Mung Dal - 1/2 cup
Small Bringal/ eggplant - 4 to 5 cut into small cubes
Red Chili Powder - 1 tsp
Coriander Powder - 2 tsp
Turmeric - 1/2 tsp (couple of pinches)
Thick Puli Vellam (tamarind juice) - 1/2 cup
Salt to Taste

Oil - 1 tbsp
Mustard Seeds - 1 tsp
Urad Dal - 1 tsp
Dried Red Chili - 1
Jeerakam - 1 tsp
Onion - 1/2 cup Finely chopped

In a pressure cooker put /12 cup of washed passi parippu & the cubed bringal. Add water just above the level of the veggies. Add salt, turmeric powder, chii powder, coriander powder. Cook on sim for up to 2 whistles. Let it then cool. Once all the steam has been released add the puli vellam and boil again for 10 minutes. Add one cup of water if the gravy becomes too thick.
In a separate saute pan heat the oil and add the mustard seeds, urad dal, red chili, jeerakam and the chopped onion. Cook until the onions are soft. Add this mixture to the bringal gravy.

Serve hot with pongal.