Bellappa Dosa

I saw pictures of the Bellappa dosa online.  It looked spongy and airy. Seemed like a variation of appam - a dosa I have not attempted to make as yet.  I cannot figure out how the dosa got its name. And I suspect addition of toddy would have given the sponginess to the dosa.  However, the recipe that I followed from Nandini Kini's blog uses a little amount of yeast.  Bellappa ideally should be had with something spicy.  But even with any other accompaniment it would taste as good.

Ingredients 
Raw Rice / Dosa Rice -  1 1/2 cups
Urad dal - 1 tbsp
Methi (fenugreek ) seeds - 1/4 tsp
Cooked rice - 1 cup
Dry yeast - 1/2 tsp
Salt to taste.

Soak rice, dal, methi for about four hours
Drain, transfer the contents to a blender and add the cooked rice
Grind to a fine paste with a little water.  This is a thickish batter.
Do not add the salt.

Now warm a little water and add the yeast.
You will see it begin to froth in a little while.

Add it to the prepared batter.
Ferment overnight.

The next morning, add salt to taste.
Heat a pan  Smear a little oil on the pan
Pour a ladle full of batter on the pan and lightly spread it out - not too thin like the ordinary dosa.

Cover the bellappa as it cooks on a slow fire.
Let the underside brown
The dosa does not need to be turned over.
When the top is cooked and the underside is browned well remove and serve.