Blanch the bathua leaves in boiling water for about 3-4 minutes.
Drain and put in chilled water immediately so that it stops cooking further, this also keeps the leaves bright and green.
Using the hand blender give the leaves a quick blend, don't make a paste out of it though.
Whisk the curd well and keep aside.
Heat the oil in a small pan and add hing to it, after a minute add mustard and jeera seeds. Once they start to crackle, add the green chillies and fry for a minute.
Add bathua and salt to the whisked curd and top with the tadka.
Served chilled, I like making it and serving after an hour, the flavours blend beautifully in that time.
Notes
Note: Some other things one can make with bathua are bhaji, stuffed paranthas, aloo bathua, bathua dal. Just about anything you do with your other greens can be done with this too. I had once eaten a bathua stuffed pie at Olive and it was OMG so yummy!
PS: Read a fabulous piece on bathua by Chef Manu Chandra here