Soak the chana dal in water for 3-4 hours, pressure cook for about 4 whistles (1 cup chanadal + 3/4 cup water).
Heat oil in a kadai, add cumin seeds and fennel seeds. When they start to crackle, add hing, dal, and all the remaining ingredients. Cook for 7-8 minutes.
Now press the dal with back of a spoon. Mix it well and allow it to cool down.
In a dhokla steamer, heat water. Grease a thali and pour 5-6 big spoon of batter on it. Steam for 5-6 minutes, then apply chanadal stuffing all over the batter and pour remaining batter on it. Sprinkle some red chilli powder and cook for further 5-6 minutes.
Heat oil in a small tempering bowl. Add mustard seeds, cumin seeds, white sesame seeds, Kashmiri chilli, dry curry patta and wait for the mixture to crackle.
When it starts to crackle, add hing. Switch off the flame. Now pour the tempering on dhokla and finally cut it into square or diamond shapes.