14 oz Patna or long grain rice

           Washed in several changes
           Of water
      7 oz Urad dal

      1 ts Salt

     10 fl Oz vegetable oil

  Soak the rice and urad dal in separate bowls of water for about 2 hours.
  The water should cover them by around 1 inch. Drain. Blend the urad dal
  with 6 fl oz water in an electric blender for 5 - 8 minutes until it is
  pale, smooth, light and airy. Empty the mixture into a large bowl.
  Put the rice and 6 tablespoons of water into the blender and blend until it
  turns into a fine granular paste. Add to the dal with the salt and mix
  gently. Cover and leave in a warm place like an airing cupboard to ferment
  for 24-26 hours. The batter should double in volume.
  Add 7 fl oz water fold in gently and leave in a warm place for a further 1
  1/2 hours. Heat 1 1/2 teaspoons of oil in a frying pan and when hot, drop 4

  fl oz of batter in the centre of the pan. Put the rounded bottom of a soup
  spoon very lightly into the center of the batter and using a slow, gentle
  and continuous spiral motion, spread the batter outwards with the back of
  the spoon until you have a pancake around 7 inches in diameter.
  Dribble 1/2 teaspoon of oil over the pancake and another 1/2 teaspoon round
  the edges. Cover and cook for 1 1/2 - 2 minutes, or until the dosa has
  turned reddish brown. Turn over and cook uncovered for a further minute or
  until the second side develops reddish spots.
  TIPS
  Urad dal is a small pale yellow split pea. Buy it from Indian grocers or
  substitute the more familiar yellow split peas available in supermarkets.
  Madhur Jaffrey's Flavours of India - Tamil Nadu
  Osas
  These nutritious pancakes from the Tamil Nadu region are versatile and can
  be eaten for breakfast as a light lunch or for dinner. They may be eaten
  plain with coconut chutney, or folded over potatoes.