The New Zealand Railways Magazine, Volume 11, Issue 11 (February 1, 1937)
White Mountain Icing
White Mountain Icing.
Sugar, 2 cups; cream of tartar, ½ teaspoon; egg (whites), 2; baking powder, ½ teaspoon; hot water, 1½ cup; lemon juice, ½ lemon.
Mix sugar, cream of tartar and baking powder, add water and let it boil without stirring. Beat whites stiffly, add boiling syrup a spoonful at a time, beating well. Keep syrup boiling, continue until about half the syrup has been added. Add lemon juice. Boil the rest of the syrup until it forms a thread, add it all at once to the mixture and continue beating over warm water until the icing will remain in shape. Pour over cake immediately.
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