Grease and line (with grease proof paper) an 8
inch round microwave dish and set to one side. An
alternative to this is to line the container with
clingfilm - as this does not absorb moisture from
the cake, it does not stick to the cake at all.
Mix the sugar, cocoa, salt, flour and
bicarbonate of soda in a mixing bowl. Make a well
and add the oil and vanilla essence. In this
recipe, the raising agent is the reaction between
the sodium bicarbonate and the vinegar (the
acetic acid in the vinegar displacing the weaker
carbonic acid in the sodium bicarbonate to
produce bubbles of carbon dioxide) - the raising
effect being lost if it is used too early or
given a chance to escape. Add the vinegar so that
it goes into the oil and therefore does not
immediately come into contact with the dry
mixture. Pour in the cold water and fold in the
mixture. Do not beat it as this will destroy the
bubbles. Pour into the tray and microwave for 10
minutes at 450 Watts (around 7 or 8 minutes for
650 watts et cetera).
When cooked, let cool and then turn out onto a
plate or board.
In a clean bowl, beat the margarine and add
the essence. Sift the icing sugar and the cocoa
powder and mix to an even consistency. Add water,
small amounts at a time while beating, until a
creamy consistency is achieved.
With a long knife, carefully slice the cake in
two, horizontally (try introducing a piece of
grease proof paper behind the knife as you do
this as this will help you to separate the two
pieces), placing the top piece down
carefully (this recipe is not super-glued
together with eggs so runs a higher risk of
breaking). Spread the filling onto the lower
piece and replace the top, making sure that the
icing goes all of the way to the edge. If
desired, more icing may be used to cover the cake
completely.