Firstly, Take 500 grams of Dosa Batter. (Check my Perfect Dosa Batter Recipe - Step by Step Recipe with Photos and Video).
Add one chopped beetroot in a blender and ¼ cup water. Grind into a paste.
Now add this beetroot paste into dosa batter and mix well until fully combined or till you achieve pink-colored dosa batter.
Now prepare the Potato Masala for Dosa as per my Recipe. (Check my Potato Masala Recipe - Step by Step Recipe with Photos and Video).
Heat a dosa Tawa on high flame.
To check if tawa is hot enough, sprinkle or spray some water on the dosa tawa, the water should sizzle away and evaporate immediately and clean the tawa with a cotton cloth. (Refer to video for the method.)
When the dosa tawa is hot enough pour a ladle of batter in the center of the hot tawa.
Immediately begin to spread the idli dosa batter from the center moving your hand in the circular motion (clockwise or anticlockwise direction) and making circles until you reach the edges i.e. spread it like regular dosa. (Refer to video for the method.)
Try to spread it as thin as possible.
You can make thin or thick dosas with this batter as per your choice.
Now drizzle some oil around the edges and also in the center.
Let the dosa cook for few minutes until the bottom of the dosa starts appearing golden brown. You need to cook only one side of the dosa, this will make the dosa very crispy.
After that put the flame on low and add some potato masala or aloo masala on the dosa.
Then scrape the sides of the dosa to release it from the pan and fold as per pic.
Now transfer the masala beetroot dosa to a plate.
Immediately Serve the crispy and yummy Beetroot Masala Dosai in Tamil style with hot and tangy Sambar, Coconut Chutneys.