Categories: Soups/stews, Cheese/eggs 
      Yield: 6 servings 
  
      3    Egg yolks 
    1/2 c  Sugar 
    1/2 ts Lemon rind; grated 
      1 ts Lemon juice 
      1 ts Vanilla (opt) 
      1 qt Buttermilk 
    1/4 c  Heavy cream; whipped (opt) 
  
  "The flavor of commercial buttermilk varies enormously from dairy to 
  dairy. Natural fresh buttermilk, if available, would be ideal for this 
  unusual summer luncheon or dessert soup, but cultured buttermilk of 
  good flavor will do almost as well." 
  With an electric beater or wire whisk, beat the egg yolks in a large 
  bowl. Gradually add the sugar, beating until the eggs fall back into 
  the bowl in a lazy ribbon when the beater is lifted. Add the grated 
  lemon rind and juice and the optional vanilla. Slowly beat in the 
  buttermilk, continuing to beat until the soup is smooth. Serve in 
  chilled bowls and float a spoonfull of unsweetened whipped cream on 
  the surface of each service if you like. Buttermilk soup is 
  traditionally served with Oat Cakes. (See recipe.)