My mother used to make this Bombay chutney a lot when we were kids. This is one of those recipes which is very simple to make and taste very yummy. This goes very well w. Chapathi, Dosa or Puri's.
Take a bowl and mix Besan and Yogurt together and make sure there are no lumps of besan then keep it aside.
Take Deep Skillet and put oil and when it is hot add mustard and curry leaves and when mustard seeds start spluttering add Onions and green chillies. When Onions turns Translucent add pinch of turmeric and then add Peas and Tomatoes and when it is cooked little bit add Potatoes and saute it until all the Veg. are cooked.
Then to the above Vegetables add Besan yogurt mix and lower the flame to medium and let it cook for 8-10 minutes and the consistency can be adjusted by adding water if it is too thick. Transfer in a bowl and granish w. Cilantro and it is ready to eat.