First wash the cauliflower florets and add it to a large pan with a pinch of salt and turmeric. Add boiling water to the cauliflower and leave it aside until needed. This will help remove any impurities from the cauliflower.

  

Add the cashews to a blender/mixer along with sufficient water and grind into a smooth paste and keep aside.

  

In a separate large pan, heat the oil and add the fennel seeds, green chilli and curry leaves. Once they start to change color, add the chopped onion and saute until translucent.

  

Now, add the the chopped tomatoes, ½ tsp salt and saute until the tomato turns mushy.

  

Now, add all the masala powders (¼ tsp turmeric, red chilli powder, coriander powder, cumin powder, garam masala) and saute until the mixture become thick and the oil starts to ooze out.

  

At this stage, add sufficient water for the masala (about ¼ cup) and add the ground cashew paste. Mix well until combined and let it come to a boil.Once the mixture starts to boil, add the cauliflower florets (drained from water) and mix well.

  

  

  

Then, remove the lid, turn the flame back to high and saute until the mixture thickens and comes to a masala consistency. Add the coriander leaves, mix well and turn off the flame and keep the masala aside.

  

Now we can start preparing the dosa. Heat a tawa, take ¾th ladle of batter and spread it into a thin dosa and sprinkle some oil to its corners and over it. Refer to my video here. Cook in medium flame until the side touching the tawa changes to golden brown, by now the top will be fully cooked as well. Place a ladle full of prepared masala at the center and fold the dosa over it.

  

  

Serve hot and enjoy with an optional side of chutney or sambar.