Make a smooth paste with the ingredients mentioned under different batters. Let them rest for 20 minutes.
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 (1/2 tsp in each batter) in dhokla batters followed by 1 tsp of water in each batter and mix them well.
Pour prepared white batter into the greased pan followed by the yellow, green, pink colored batter one by one.

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.

For Tempering: Heat oil in a small pan, first add the mustard seeds. Let them papaya first. Now add chopped chilies, sesame seeds, flaxseeds. Saute for a minute.
Add 1/4 cup of water to tempering and allow mixture to boil for a minute.
Switch off the flame and add lemon juice. Mix it well.
Spread tempering over dhokla and garnish with chopped coriander leaves.
Cut into the desired shape and enjoy with your favorite chutney.

Tips :

For Beetroot Puree:

Boil small beetroot in a pressure cooker and then peel the boiled beetroot.
Cut boiled beetroot into small cubes and grind with 1/4 cup of water.
Make a smooth puree. It yields 1/2 cup of beetroot puree.

For Spinach Puree:

Boiled 1 cup chopped spinach with 1/4 cup of water in a saucepan for 5 minutes.
After boiling immediately add boiled palak into cold water. It helps to retain it's bright green Colour. Grind boiled spinach with 2 tbsp of water into a smooth puree.
It yields 1/2 cup of spinach puree.