Drain water from the overnight soaked kala chana and wash it with fresh tap water.
Put in a pressure cooker along with 3 cups water and 3/4tsp salt. Pressure-cook for 5 whistles or 20 minutes until well done.
Meanwhile, in a pot heat desi ghee and add chopped onions and all the dry spices (green cardamoms, black cardamoms, cloves, star anise, cinnamon sticks, cumin seeds and mace).
When the onions are soft add potatoes and fry on low heat to avoid the spices from burning. NOTE: No need to caramelize or brown the onions because the water that we are going to use from the chickpeas is very dark in color already.
When the potatoes start to look translucent at the edges, add salt, red chili powder, cumin powder, coriander powder and dried fenugreek. Cook on low until the potatoes are 90% done.
Lastly, drain the rice and add to the potatoes. At this stage turn the flame to medium and sauté the rice until the moisture in the pot has been absorbed by the rice.
Now drain the chickpeas (reserving the liquid) and add to the rice.
Measure the chickpea liquid using the cup and add to the rice. We need a total of 4 cups of water. I had almost 2 cups of chickpea water so I added 2 cups of plain water to make a total 4 cups.
Mix and turn the flame Medium to high.
When the rice absorbs half of the water, add green chilies, fresh coriander and fresh mint. Give a gentle stir.
Allow all the water to be absorbed by the rice, cover and cook the rice on lowest possible flame (dum) for 7-10 minutes.