In another pan, add 1 tbsp of oil/ghee, add little cumin seeds, let it crackle.
Add chopped onion, fry till it is light brown.
Add tomato puree(grind ginger with tomato), cook for a minute then add curd and keep mixing it till it mixes with onion-tomato masala. Before adding curd beat it nicely to smooth consistency.
Cook the masala really well till oil/ghee separates. Add Chole to it and mix nicely. Add chole/chickpea water . Mash some chole with a ladle or wooden spoon and let it cook for 20 minutes on low flame.
Adjust the water if you feel the chole are too dry, also adjust the amount salt and the dry chana masala or spice level as per your taste. Use boiled chole water that we retained.
After 20 minutes switch off the flame and keep the Chole covered. It helps to fully absorb the masala/spices and enhances the flavour.
Reheat when ready to serve. Add some water if Chole curry thickens. We don't need watery curry for this but too dry Chole won't also go well with Bhature.