Beat the eggs. Mix the flour to a smooth paste with a little water. Put the eggs and the flour paste into a saucepan, add the sugar and juice and place over a very low flame or in a double boiler so that the contents will not boil. Whisk until the mixture thickens. It will be light and frothy and should be served at once. Note: Sugar: recipe calls for 1/4 lb. Lump sugar