Steam cook the corn rava by adding 3/4 cup water for about 10-15 minutes.
Heat oil in a pan, add mustard seeds, let it splutter, then add onions. Saute till transparent and add required salt.
Then add chopped green chilly and curry leaves. Saute for few seconds.
Finally add steamed corn rava and mix it well. Keep stirring for 5 minutes. Sprinkle some water only if needed. Reduce the flame, cover and cook it for 2 more minutes.