Preheat oven to moderate 180oC.
Brush a deep, 20cm round tin
with melted butter or oil. Line base and side with paper, grease
paper.
Sift the flour, cocoa and soda into
a large mixing bowl. Add sugar.
Pour the combined eggs, buttermilk,
essence and butter onto dry ingredients.
Using electric beaters, beat on low
speed for 3 minute or until just moistened.
Beat the mixture on high speed for 5
minutes or until mixture is free of lumps and increased in volume.
Pour mixture into prepared tin, smooth
the surface.
Bake for 40 to 50 minutes or until skewer comes out clean when
inserted in centre of cake.
Leave cake in the tin 15 minutes before
turning onto wire rack to cool.
To make the Feathered Icing :
Combine butter and chocolate in a small pan, stir over a low heat until
melted, remove from heat. Cool.
Cut the done off the cake to level the
surface. Cut cake in half horizontally.
Spread whipped cream over half of cake
from which dome was sliced. Sandwich with the other layer. Spread icing
over top using flat-bladed knife. Place white chocolate in glass bowl.
Stir over barely simmering water until melted, remove from heat. Cool
slightly.
Spoon melted chocolate into a small
paper icing bag, seal open end. Snip tip off the piping bag, pipe 8 to
10 small to large circles around the top of the cake.
Drag a skewer from the centre circle to the outside of the cake. Clean
the skewer and repeat this process, working around the cake in wedges.
This is called feathering.