Blanch or steam the spinach leaves along with stalk. Allow it to cool. Once cooled puree it along with ginger and green chilies in a mixer grinder. Puree should be around 1 cup.
Grind the soaked moong dal with as little water as possible.
In a wide bowl, add in the ground moong dal, spinach puree, curd and oil. Mix well. Add a little water at a time to make a batter. The batter should be of dropping consistency, neither too thin nor too thick.
Now add in salt and lemon juice and mix well so that there are no lumps in the batter. Let the batter rest for about 5 to 10 minutes.
Meanwhile grease a steamer plates and keep it ready. Prepare the steamer with water and keep aside.
Once the batter has rested, stir in the fruit salt and mix well without beating it too much. Just mix until the fruit salt is combined well into the batter.
Immediately pour the batter in the greased plates and place it into the steamer for steaming.
Steam on high in the steamer for around 15-20 minutes until when a tester inserted inside comes out clean.
Remove the steamed palak dhokla's from the steamer and allow it cool for 10 minutes.
Heat oil in a small pan; add asafoetida, mustard seeds, sesame seeds and allow them to crackle. Turn off the heat and gradually add the 3 tablespoons of water to the seasoning. Take care as the oil will start spluttering. Adding water is necessary as it helps in keeping the dhokla soft and moist.
Drizzle this seasoning on top of the Palak Dhokla. Cut the dhokla into square pieces and serve warm.