Soak all the dhal and rice in water for 6 to 7 hours. Grind it in a blender well, don't make it too smooth, it should be little bit coarse. Finally add the dried red chilli and grind it once again until it's finely chopped. The batter should be of pouring consistency.
Prepare the cauliflower by separating the florets and boil them in the water for few minutes. Don't let them boil for too long and cook. Remove the Cauliflower from water and grate finely or chop it up finely.
Now add the cauliflower, coriander leaves and chopped onion to the adai batter and mix it well (it will be a bit thick after adding the cauliflower, so add some water and make the batter a little thin.)
Heat a tawa or a pan, oil it, pour a ladleful of batter in the pan and spread it with a ladle in a circular motion to form a round shape. Apply oil along the sides.
Cook for 2 to 3 minutes, turn it over other side, leave it for about 2 minutes and take it out.
Repeat the same with rest of the batter. Serve it hot with chutneys or sambar.
Grind all the ingredients with juice of 1/2 a lemon, make it into a paste. Serve it with adai.