Wash the coriander leaves and keep it aside for drying.
Dry roast daalia or gram flour, whichever you are using, on a medium heat. Daalia is roasted bengal gram so doesn't need much of roasting again. But if using gram flour, then roast until the raw taste is gone. Keep stirring in the pan as it has a tendency to burn fast. Make sure it doesn't burn.
Once the daalia/gram flour cools down, grind it along with salt, asafetida, chaat masala, chopped ginger, green chilies, coriander leaves (making sure these are completely dry), turmeric powder, lemon juice. Grind it to a fine paste.
The consistency of this would be like that of a soft dough. Store it in an airtight container inside a refrigerator. This can stay fresh for several days.
To use, add part of it in a bhel mix. Best way to incorporate it in bhel is to mix it with hands, such that there are no lumps.