You know, I have seen in some homes, they make mor kootu (yogurt gravy) only if it turns sour.
Not in my house. My Maternal Grandma, Mrs Vimalam Ramamurthy, would make fresh yogurt and then use that to make the Kootu or Avial.
I also have to say, making this kootu is an art. You have got to be careful not let the yogurt separate.
What you need to make this wonderful dish.
For Soaking (at least half an hour before)
--- 2 tsp Jeera
--- 1 tsp rice
--- 1 tsp Channa Dal
--- 2 or 3 green chillies (add more if you like it spicy)
--- about 5 tbsp of coconut
For the Kootu
----take about 8 cups of winter melon (washed, take of skin and cut in 1 inch pieces)
---1/2 cup of water
--- salt (add to taste)
--- 3 cups of thick yogurt ( I use store bought mostly because of the thickness, since the one I make at home tends to be watery (I use skim milk to make yogurt at home)
---Take a vessel, and add the winter melon, and the water and salt.
---Keep on low fire.
---Winter melon has lot of water content, so you don't need to add too much water.
when this is boiling, grind the masala, which has soaked to a smooth mixture.
---add the masala slowly and stir it well
---reduce fire and add the yogurt to this
---heat only for 5 to 10 minutes making sure the yogurt doesn't separate
--- give tadka to this with oil, mustard, red chillies and curry leaves.
You can eat this with rice or rotis