Whisk semolina, AP flour & rice flour in a medium bowl. Add water and whisk into a smooth batter with no lumps. I ended up adding about 3 cups of water.

Heat 1tbsp oil in a small sauce pan and add mustard and cumin seeds. Once the seeds start to splutter, add the oil to the batter.

Add the rest of the ingredients and mix well. Cover and rest for at least 1 hour.

Heat a non-stick or cast-iron griddle on medium-high flame and once ready, pour the batter one ladle at a time to make a round dosa/ crepe. Here's a pictorial on how to make rawa dosas. Thanks Sailu.

Once done, serve hot with your favorite chutney. I served with Sreelu's no-cook, no chop Chutney & green pepper Sambar.