Cut the vazhaipoo and soak it in water. If you are cutting the one day before, add few drops of butter milk to the water and keep it outside. If you want, you can keep it in the refrigerator.
Soak the chana dal for 30 minutes.
In a pan, add the vazhaipoo (drain water before adding) and add turmeric powder, salt, and asafoetida.
Add the thin tamarind extract to this.
Cook the soaked channa dal and toor dal in a pressure cooker. Keep both in different vessels while cooking.
Roast the ingredients given under the head, "to roast and grind".
Grind this into a fine paste and keep it aside.
Add the cooked channa dal to the pan, along with the ground paste.
Mix well and add the cooked toor dal to this.
Dry roast the coconut (3 tbsp) in a pan until golden brown, then add to the kootu.
Mix well, and if needed, add 1/2 cup of water. Add jaggery to this and mix well.
Temper with mustard seeds and curry leaves in coconut oil or normal cooking oil.
Switch off the flame. Kootu is ready to serve.