Soak chanas overnight. Next morning drain them and transfer to a pressure cooker. Add salt, turmeric, red chilli powder and a pinch of hing and 2.5 cups of water.
Pressure cook for 10-15 minutes.
Add juice of one lemon.( optional)
Patties:
Boil potatoes and mash them while they are still hot.
Add salt, red chilli powder and cornflour.
Make round patties and shallow fry them.
To Assemble:
Keep all the ingredients ready before frying patties. Ragda should be hot while serving.