Wash and soak the whole moong daal for overnight.
Grind the soaked whole moong daal with ginger, green chilli, coriander leaves, besan or gram flour, curd and very little water (2 tbsp) to a semi coarse paste.
Keep 2 cups of water in deep kadai and put a stand in it. Cover it and let it boil for 5 minutes. Now add Eno in a dhokla batter and pour 1 tsp of lemon juice over it. Mix it well.

Pour prepared batter into the greased pan and place it on the stand inside the kadai.
Cover the kadai and steam the dhokla on high flame for 15 – 20 minutes.
To check the doneness, insert a toothpick. If the mixture does not stick, it means the dhokla is done (If the toothpick has the batter on it, then steam dhokla for another 5 minutes).

Switch off the flame and allow dhokla to cool completely.
Insert a knife around the edges to loosen up dhokla. Flip it over onto a plate and cut into squares.

For Tempering:

Heat oil in a small pan and add the mustard seeds. Let them papaya first.
Then add white sesame and allow to crackle.
Then add chopped chilli, sugar. Now add water, lemon juice and let it boil for 1 minute. Switch off the flame.
Spread tempering over dhokla and garnish with chopped coriander leaves cut into the desired shape and enjoy.