In a kadai/wok add the oil.
Once hot , add in the mustard seeds.
Let the mustard seeds splutter.
Now add the onion, curry leaves, 1 tablespoon cashew and green chilly.
Saute this for a few minutes until onion is translucent.
Now add the 2 cups of water, salt and 1/2 Cup chopped coriander.
Let this mixture come to a boil.
Once the water starts boiling, reduce the flame to minimum.
Add the lemon juice and next add the Rava/semolina, stirring vigorously.
Keep on stirring the mixture continuously until you get a lumpy mass, or it starts leaving edges of the wok/kadai.
Switch off, cover and let it sit for 5 minutes.
The rava will absorb water.
Garnish with chopped coriander, cashew and serve.