Steam cook the raw banana for just 10 minutes. Leave it for some time.
Cut the onion, green chilli and ginger into small slices. Grate the coconut.
Now remove the outer skin of the steamed raw banana. Grate the banana with the carrot grater.
Now place the pan in the stove. After the pan turns hot, add coconut oil, mustard seeds and urad dhal. Then add curry leaves.
Now add the sliced onion, green chilli and the ginger. Stir it for at least 5 minutes in medium flame until it turns into light brown colour.
After that, add the grated banana and salt(according to your taste), stir it gently for some time(5 minutes) in medium flame.
Finally add the grated coconut and stir it for 2 to 3 minutes and remove from the stove. Now the raw banana puttu is ready to serve.