Wash thoroughly all three main ingredients - Rice, urad dal, chana dal. Soak in water for at least 4 hours.
Then grind in the mixer by adding green chillies, ginger,dahi and water as needed. Consistency should be medium.
Pour batter in a vessel, cover lid, and keep it for at least 6 - 8 hours for fermentation.
After fermented cook dhokla in dhokla cooker or in a kadai, pour water, keep any stand or metal ring, so water shouldn't go in dhokla plate, while steaming, put a deep plate on it.
Turn on gas on medium flame.
On the other side, add salt, turmeric, oil, eno soda in batter, mix well, grease plate with oil, pour the batter in the plate, cover with a lid, cook for at least 6 - 8 minutes, check it.
Take out plate keep aside for a couple of minutes to cool, sprinkle red chilli powder, cut into pieces..
Khatta dhokla is ready to serve. Serve with green chutney or anything of your choice.
Enjoy hot, try once, will craving for it.