Cut the pumpkin into cubes.
Soak the tamarind in luke warm water for ½ hour. Squeeze the juice and keep it aside.
Heat oil in a kadai. Add mustard seeds, fenugreek seeds, curry leaves and asafoetida..Once the mustard crackles, add the cut pumpkin cubes, sauté it for 3 minutes in medium flame.
Now put 3 tsp of the vathal kuzhambu spice powder, mix well. Fry for few seconds.
Now add the tamarind juice plus 1 cup of water.
Add salt and let everything boil for 5-6 minutes in medium flame.
Add gram flour and 2 tsp water. Make it into a paste and pour this into the boiling Kuzhambu and boil for few minutes to get the right thickness of the kuzhambu.
Add jaggery, cook for 1 minute in low flame.
Switch off the fire. Serve with hot rice and karimedhu/ curry of your choice.