Combine all the ingredients mentioned under the khatta meethi chutney into a smooth paste .
Add little water while grinding if required.
Cut the tomatoes and scoop out the seeds from the inside.
Chop tomato, capsicum, and potato into small cubes.
Heat butter in a kadai and add the cumin seeds.
When they crackle add the boiled chana, potatoes, tomatoes, and capsicum and cook for a minute.
Remove from flame and allow it to cool.
When cool, add the khatta meethi chutney , salt, lemon juice, and coriander leaves . Mix well.
Serve immediately.