Mix all the ingredients given for batter, except the Eno's fruit salt, using enough water (about 1 1/2 cups u2013 this is just an estimate) to make a thick batter. The batter should thickly coat your spatula. Keep aside for about 15 minutes. The semolina will absorb some of the water in the batter, so the batter will become thicker after standing for 15 minutes. Adjust the consistency with a couple of spoons of water before steam cooking.
On the stove top, get your steamer (whatever you use for steam cooking food) ready. Once the water is boiling and the steam is rising well from the steamer, add the Enos' fruit salt to the batter. Sprinkle a little water over the fruit salt. It will start bubbling and frothing.
Stir the batter well enough to mix in the fruit salt. Pour the batter into a well oiled round (9" or 10")or square cake tin (8" by 8") or a thali (a round steel plate with high sides) and steam cook for about 10 to 12 minutes or till a skewer comes out of the dhokla clean.
For the tempering, heat the oil and add the mustard seeds. When they start to splutter, add the sesame seeds, chopped chillies, asafetida and curry leaves. Add the 1 tbsp of water and pour this over the steamed dhokla. Garnish with coriander and coconut.
Cut the dhokla into squares and serve warm or at room temperature with green chutney or if preferred with tomato ketchup.