Whisk together the curd and besan to get a lump-free mix.
Add 3 cups of water and mix well. Keep aside.
Heat the ghee in a kadhai (wok or heavy-bottomed pan) and add the cumin seeds and mustard seeds.
When the seeds crackle, add the asafetida and sauté for a few seconds.
Add the prepared curd-besan mixture, curry leaves, salt, ginger-green chili paste and sugar, mix well and bring to a boil for 2 minutes, stirring continuously.
Reduce the flame and simmer for 10-12 minutes, stirring occasionally.