Preheat oven to 180 degrees Celsius. Grease and line a 20cm/8 inch sponge cake tin with baking paper.
Whisk the eggs with a mixer until pale, fluffy and thickened. Add sugar and beat until completely mixed and dissolved. Add the cold water and fold with a metal spoon.
Place the salt, corn flour and baking powder in a metric cup, then fill to the top with plain flour.
Slice sponge in half and spread whipped cream between halves.
Combine icing sugar and pulp and whisk until well combined. Spread over top.