Add ginger, garlic, and green chilies to a mortar and pestle and crush to make a coarse paste.
Sieve besan using a large sieve to avoid any lumps.
Add chili powder, turmeric powder, and garam masala powder to the bowl and mix well.
Add water slowly and whisk to make a lump-free batter. If by any chance there are still lumps in the batter, you can pass the batter through a mesh strainer.
Heat oil in a pan over medium-high heat.
Once the oil is hot, add asafetida, mustard seeds, and cumin seeds, and let them crackle for 4-5 seconds.
Add garlic green chili paste, and curry leaves, and saute for 20-30 seconds.
Now add cilantro and onions and cook for 1 minute.
Reduce the heat to low.
Add the besan mixture and salt to the pan and mix well.
Cook the pithla on low heat for 7-8 minutes, stirring frequently. The consistency of pithla is like a thick paste.
Garnish with fresh coriander and serve hot.
Video
Notes
You can add some yogurt to the besan mixture to make dahi pithla.Add chopped greens like fenugreek leaves (methi), spinach(palak), or spring onions to the pithla to make a new version. You can also add chopped green bell peppers (capsicum).