Cut water melon rind , wash it put it in the grinder. Add Rava rice flour, besan and water grind it properly and make a semi flowing consistency batter . Put salt and red chilli powder,mix well . Now take a non stick pan , grease it when it slightly hot pour the batter one scoop . Spread some onion. Cover the lid and cook it in low medium flame till the pan cake cook nicely. Serve hot with sauce or green chutney. You can make it in oven also in convection mode at 200* C for 8-10 min.