Preheat the oven to 170°C/ fan oven 150°C, 325°F, Gas Mark 3.
Sieve together the flour and cocoa powder.
Beat the butter and sugar together until light and creamy. Add one egg and beat until well mixed. Add the other egg and beat well. Add the final egg along with the almond extract and a tablespoon of flour and cocoa mix and beat again.
Fold in the remaining flour and cocoa powder. Pour into a Pyrex Non-Stick 26x19cm Rectangular Tin and bake 30 – 35 minutes or until firm to the touch. Test by inserting a skewer into the centre if the cake, if it comes out clean, the cake is ready. Remove from the tin and leave to cool.
For the macadamia butter icing: Whiz the macadamia in a mini food processor until finely chopped. Beat the butter in a large bowl until soft. Add half the icing sugar and beat until smooth. Then add the remaining icing sugar and macadamia nut. Beat until smooth and creamy.
When the cake is cooled enough to handle. Trim the edges of the cake and slice horizontally into 3 layers. Place the bottom layer on a chopping board and spread with half the butter icing. Put the middle layer on top and spread with most of the remaining butter icing, keeping a few teaspoons for later. Add the final layer. Chill the cake until the butter icing is set. Cut the cake into 16 squares.
Make the chocolate icing. Melt the chocolate and butter together with 4 tbsp water in a microwave or a bowl set over a saucepan of simmering water. Mix in the icing sugar.
Place the cake squares on a wire cooling rack over a tray or chopping board. Top each cake with a blob of the remaining butter icing. Gently pour the chocolate icing over the cakes letting it drizzle over the edges. Leave to cool. Top with the chocolate decorations. Serve as a dessert or for afternoon tea.
Tip: For added indulgence drizzle the cake with Amaretto.