Heat oil in a pressure and add hing, roast till one minute and add jeera seeds. Roast till they turn golden brown.
Add the grated onions to it and fry till deep brown in color, constantly stirring.
At this stage, add the ginger garlic paste and tomato puree. Fry till the oil starts to leave the side.
At this stage, add all the dry masalas apart from garam masala, Fry further for one minute.
Add the potatoes and cholia at this stage and fry for 2-3 minutes till they are coated in masalas.
Add enough water to just cover the cholia and aloo. Close the pressure cooker. After the first whistle, lower the gas and cook for 5-6 minutes.
Switch off the gas and let the pressure release on its own before opening the pressure cooker.
Add the garam masala and mix. Serve hot with phulkas.