This is quite a tall order.
I make dosai at home but the process is quite involved.
If you still want to give it a shot, here is the recipe.
Start the preparation 2 days before.
Soak seperately 3 cups rice (thai rice prefered) and 1 cup whole
urad without skin (you can get this at an Indian store).
Soak for ~ 8 hours.
Grind the above seperately to a fine paste with the help of the
The consistency should be like a pancake batter.
Mix both the pastes and let the mixture ferment in a warm atmosphere
for at least 15 -16 hours.
The batter should ferment to double in size.
Add salt to taste and mix it well.
Put a heavy seasoned skillet on the stove.
When the skillet is very hot sprinkle some water and it should splutter),
pour a ladle full of the batter and quickly spread it around in
circular motion till you get a thin large dosa.
The heat should be regulated so it does not burn.
Apply a dab of oil/margarine or butter on top.
With a flat spatula, try to up root the dosa.
If this is done properly it should come of easily and not stick
Turn it over and cook the other side for a minute.
Wipe the skillet with a tissue before starting another dosa.