Heat oven to 180C/fan 160C/gas 4. Butter
and line the base of a 18 x 28cm cake tin
or tray. Put the butter and sugar into a bowl;
beat together with electric hand beaters until
light and fluffy. add the eggs a little at a time,
beating well between each addition.
Sieve the flour, cocoa and bicarbonate
of soda into the bowl, then tip in any
bran left in the sieve. Pour in the natural
yogurt. Stir everything to a smooth mixture
and spoon into the prepared tin. Bake for
20-25 mins until just firm and shrinking
away from the sides of the tin. Cool in the
tin for 5 mins, then turn onto a wire rack
to cool completely.
For the icing, sieve the icing sugar and
cocoa into a bowl, then pour in the butter
and 2 tbsp just-boiled water. Stir together
to a smooth, spreadable consistency. if it’s
too stiff, very carefully add a little more
boiling water, drop by drop.
Spread the icing over the top of the cake,
using a palette knife dipped in hot water. Will
keep in an airtight container for up to 1 week.
Melt the chocolates in three different
bowls in the microwave on High for 1 min
or over a pan of simmering water. Spoon
the melted chocolates into three plastic
disposable piping bags. Snip the ends off
and pipe 12 simple shapes on top of the
cake. Leave to set. Just before serving,
cut the cake into 12 squares and push
in the candles.