Take leftover refrigerated idlis or steam fresh idlis and let them cool down before use.
Then cut these idlis into bite-sized shapes so that they mix easily.
Now in a bowl, whisk thick curd with a pinch of salt and roasted cumin.
Prepare the tadka by heating oil in a pan and adding curry leaves, mustard seeds, green chilies, and urad dal.
Gradually add the idlis to the tadka and gently toss. Then, pour the curd over it.
Now, let the curd-idli get chilled add it to the refrigerator for 10-15 minutes.
Your tasty South Indian style dahi idli is ready, garnish it with fresh coriander, pomegranate seeds or boondi and serve it chill.