Firstly, prepare a batter of curd and gram flour in a big bowl. Stir until all lumps are dissolved. Add 2 cup water into it and mix really well until smooth. Now add green chilly, ginger and green coriander in a mixture grinder and make a fine paste. Mix this paste in gram flour-curd batter.
Preheat oil in a pan and keep the rest for later use. When oil is sufficiently hot add brown mustard seeds and keep rest. After sauteing brown mustard seeds, add gram flour-curd batter. Increase the flame. Stir it constantly and cook until it starts simmering. When it starts simmering add salt, sugar, red chilly powder and cook on low flame for 6-7 minutes. Stir the chutney at regular intervals.
Chutney is now ready. Turn off the flame and take out chutney in any bowl. To enhance the flavor of chutney, add a tadka from top. For this take little amount of oil in a pan and heat sufficiently. Add brown mustard seeds in oil, turn off the flame and add red chilly powder as well. Now pour the tadka over chutney and mix well.
Garnish with green coriander. Luscious and delicious besan chutney is now ready.