Kaalan ( ) is a Keralite dish from South India, made of yoghurt, coconut and a raw fruit nendra kaaya or a tuber like the chena (yam).
It is very thick, which distinguishes it from a similar curry known as pulisseri, and more sour than avial. For the same reason, kaalan can last longer when stored. In many preparations, more pepper and/or chillies are added to make the kaalan spicy, in addition to its signature sour taste.
Kaalan is typically served as part of the Sadya.