First, prepare the Dhokla.
Put all the ingredients except for the water in a big bowl, then add warm water and beat very well using a fork. Really whisk it properly at this stage.
Then, heat 2 tbsp. oil and add a pinch of chopped limro/curry leaves and half tsp. rai/mustard seeds. Turn off the heat and add this oil/tarka mixture into the batter and mix it in very well.
Now the Dhokla/Khaman batter has to be steamed.
Put the wire rack inside the big pot and add water into it. Then place the 8" pan whilst it is still empty on the wire rack. Take care that the water does not go into the 8" pan, it should be at a lower level but not too low that it will dry out during the cooking process. Turn on the heat and cover the big pot with a tight lid. Heat until the 8" pan is very hot, it needs to be heated like this before the batter goes into it for best results.
While it's heating, add the 1 tsp. of Eno salt into the prepared batter. It will froth very quickly. Carefully remove the heated 8" pan from the pot, add the batter into it, level it carefully, then put it carefully back in the pot. Cover the pot tightly once more and keep the heat on high. Steam for about 15 minutes.
Once the 15 minutes are up, open the pot and stick a sharp knife into the Dhokla cake. If it comes out clean, your dhokla cake is ready. If there is still some batter sticking to it, cover again and keep steaming for a few more minutes.
Once ready, remove the Dhokla pan carefully from the big pot, and place it on a wire rack to cool slightly. In the meantime, prepare the sauce.
Heat the oil, add the rai and sesame seeds, followed by the limro leaves, garlic paste, tomato paste, ketchup, salt, sugar, chili powder and lemon juice. Stir for a couple of seconds then add quarter cup of water. Simmer together on low heat for a few minutes, then turn off the heat. Your sauce is done!
Pour this sauce over the Dhokla. Once the Dhokla has cooled completely, careful slice into it using a sharp knife and remove the pieces.
Serve warm and enjoy! :)