In a pan take oil, mustard, cumin, hing, urad and chana dal. As seeds splutter and dal turns pinkish add turmeric, green chillies, curry leaves, onions and saute till soft.add ginger garlic and saute.

Add potatoes, salt, sugar,and mix and cook for 3-5 mins. Add lemon juice and mix

Ready to serve hot with roti, puri, dosa, rice