Make batter base: Whisk 3.5 cups water with 2 tablespoon yogurt in a large bowl.
Add dry ingredients: Mix in 1 cup rava, ½ cup rice flour, ¼ cup maida, and 1 teaspoon salt until lump free.
Add aromatics: Stir in green chili, ginger, cumin, curry leaves, coriander, and onion until evenly distributed.
Rest batter: Cover and let sit for 15-20 minutes.
Stir thoroughly: Mix batter well, scraping bottom of bowl where rava settles.
Heat pan: Place non stick or cast iron pan on medium heat for 1 minute.
Test temperature: Splash water on pan; it should bubble and evaporate immediately.
Pour batter: Stir batter, then pour in small amounts all over pan starting from edges, moving inward. Leave gaps.
Cook undisturbed: Let cook 5-8 minutes without touching or spreading.
Check dryness: Touch top of dosa with finger; surface should feel completely dry.
Add oil: Drizzle oil around edges and let cook another 30 seconds to 1 minute.
Check crispiness: Dosa is ready when edges are golden and bottom sounds crispy when tapped.
Fold and serve: Use wide spatula to fold dosa in half and serve immediately with chutney or sambar.