Mix first 1/2 cup curds with 1/2 water. To this add the besan and mix well to get a lump less batter, the consistency should be of idli batter, more of dropping not pouring consistency. Add the soda. Keep it aside to rise for 1 hour. If you are using a pressure cooker, fill the pan with water, place a plate over which you will have use a plate for steaming the dhoklas. Thali plate can be used for steaming To the batter mix in the citric acid, oil, salt, sugar, green chili paste and turmeric powder. Mix well. This has to be done just before pouring to the plate.
Meanwhile have the pan on stove, and let the water start boiling. When the water reaches the rolling stage, you can mix the eno to the batter (Save little of eno for dusting on the plate), mix gently, you will see bubbles coming out. I dint have a thali plate which would fit my pressure cooker and those who would were too deep and narrow for making a proper Dhokla. So I used my Baking tin which fit perfectly in my Rice Cooker and steam cooked the batter. Dust or sprinkle the plate with eno. Then immediately pour the batter to the plate. Place the plate carefully inside the pressure pan and cover with lid. You need not use the whistle. After covering you will find steam coming out of the outlet, simmer and don't disturb for almost 5 -7 minutes. The batter should be filled to only 1/2 as it will rise up. After adding eno the batter should not rest. Amount of sugar can be increased on preference. Dhokla can also be steamed in kadai filled with water and a plated titled over it.
After 5 -7 minutes, remove the lid and proof it using toothpick or knife. If the knife comes out clean and does not have any batter sticking, then its done. Cover back and let it remain on flame for 1 min and switch off the gas and allow it for 5 minutes.
In a bowl, mix 3 tsp of water along with a tsp of oil. Remove the plate from the pan, pour the water and oil mix over the top. For seasoning, heat a pan with oil, add curry leaves, sesame seeds, mustard seeds and finely chopped green chilies. When mustard starts popping, remove and pour over the dhokla
If you want perfect shaped ones and not the crumbling, cut and handle gently. I cut them out, after slightly cooling them, into squares. I then served them with Tamarind Chutney and Green chutney. They are good on their own too.
(Note: I dint know how much a packet contains since I have a bottle so I assumed 1-1/4 tsp of Eno fruit salt)