Using a blender (or a whisk), mix besan, yogurt and water very well. Make sure there are no lumps. Set aside.
In a wide saucepan on medium-high heat, add 3 tablespoons of oil and add the onions. Saute until they turn golden-brown.
Add the ginger-garlic paste and cumin seeds and saute for 5-7 seconds.
Then add the following spices - red chili powder, turmeric and salt and add a few splashes of water to prevent the spices from burning. Saute for 30 seconds.
Then immediately add the besan-yogurt mixture and turn the HEAT TO HIGH (this will prevent the yogurt from curdling).
At this point, keep stirring until the kadhi mixture comes to a vigorous boil (it may also start rising up the saucepan so be careful).
Then REDUCE the heat to MEDIUM so it starts simmering.
Place the lid on the saucepan leaving a small space. Do not cover it completely or the kadhi will boil over.
Allow it to simmer for 1 hour.
Then turn off the heat