Combine curd, gram flour, turmeric powder, red chili powder, coriander powder, and cumin powder. Whisk to a smooth and lump free paste. Add 1 Cup of water. Whisk once again to a spoon dropping consistency.
Heat refined oil in a kadhai. Add mustard seeds, cumin, fenugreek seeds, asafoetida, ginger, and green chili paste. Saute for 50 - 60 seconds.
Add whisked curd and remaining 450 ml water. Stir to combine. Simmer the kadhi over low heat for 20 - 25 minutes. Season with salt. Stir at regular intervals.
Once kadhi thickens a bit and the raw smell of gram flour wafts away, prepare tadka.
Heat ghee in a tadka pan. Add curry leaves, dried red chilies, and red chili powder. Cook only for 20 - 30 seconds. Turn off the heat.
Pour tadka over the simmering kadhi. Add kasuri methi, boondi, and fresh coriander leaves. Stir to combine. Cover and simmer the kadhi over low heat for 5 minutes.
Serve hot Rajasthani Kadhi with rice and papad.