In a mixture jar, add rice, chana dal, and urad dal. Grind it into a coarse powder.
Now, add grinded mixture, Rava, hing, turmeric powder, salt, and sugar to a mixing bowl. Mix well.
Then add buttermilk gradually and make the medium thick and flowing batter.
Add 1 tbsp oil and whisk batter with hand for 3-4 minutes and rest batter for 20-25 minutes.
Meanwhile in a pan, add 1 tbsp oil, ginger paste, and green chili paste. Sauté it for a minute.
Then add chopped cabbage, grated carrot, capsicum and boiled corn, chopped bottle gourd (lauki) pieces, and salt. Sauté till vegetables become slightly soft.
Switch off the gas and add sauté vegetables and coriander leaves into dhokla batter. mix well.
Now, Divide the batter into two parts.
Meanwhile, add water to the pan—cover, and steam for 5 minutes.
Add Eno fruit salt into the batter & mix in one direction.
Grease the dhokla plate with oil & pour the mixture into the plate.
Sprinkle red chili powder over the mixture and on one plate do not add red chili powder.
Steam in idli-dhokla steamer or Kadai for 10 min on high-medium flame.
Once done take out the plate from the steamer & allow it to cool for 5-10 min.
Apply some oil to cooked dhokla.
Cut into the desired shape.
Serve khatta dhokla with oil or sprinkle some dry garlic chutney and sev on it.