Take an Amritsari vadi and break it into 4-5 pieces. Heat oil in a cooker and fry the vadis on low flame, turning to all sides till brown from all sides. Remove the vadis and reserve.In the same oil, add cumin seeds. When they splutter, add the onion paste and cook on low flame till golden.Now add all the dry spices. Cook for few seconds.Add tomato puree. Cook till oil starts to separate.Add the chopped potatoes, vadi.Mix well and Cook for a minute for all the masala to coat well.