Combine buttermilk with turmeric, coriander powder, besan (Gram Flour), and mix well with a whisk until smooth.
Heat oil in a pan, add mustard seeds, cumin seeds, hing (Asafetida), and curry leaves. Once they splutter, add the chopped onion and saute.
Add the crushed (green chilli, ginger, and garlic). Saute for a couple of minutes.
Add Turmeric Powder and mix it well.
Add boiled potato pieces and saute for 2-3 minutes.
Pour the prepared buttermilk mixture into the pan while stirring continuously to prevent lumps.
Add salt to taste and mix well. You can add water to adjust the consistency. Add coriander leaves and Bring to a simmer, stirring constantly.
Serve the hot kadhi with Chapati, Bhakari.