Never knew that Olan is so easy to make. If 'd known, would have tried it much much before.
Yam(chena), Chowli( van payar), Chillies and coconut milk is al u need.
Take a handful of chowli, soak it over night. Take a medium yam slice , cut into pieces. 5-6 chillies (cut into 2) .. put them all in pressure cooker with some water and whistle ( i am not sure, how many , i guess 2-3 is enough). Turn off the stove. Smash them well. Add a cup of coconut milk. Required salt. Make tadka with mustard seeds and curry leaves. and pour it over. U r Done...