Cooking oil spray, to grease
½ cup baking cocoa
¾ cup firmly packed dark brown sugar
1 cup boiling water
200g butter, chopped, softened
½ cup caster sugar
2 eggs, lightly beaten
1½ cups plain flour
½ tsp baking powder
1 tsp bicarbonate of soda
Chocolate Ganache Icing
300ml thickened cream
400g dark cooking chocolate, chopped
Preheat oven to 180C. Grease the bases and sides of two 20cm round tins with cooking oil spray. Line the bases with baking paper.
Put cocoa and dark brown sugar in a medium bowl. Add water and whisk until smooth. Set aside.
Put butter and caster sugar in a large bowl and beat with electric beaters until light and fluffy. Add the eggs one at a time, beating well after each addition.
Sift flour, baking powder and bicarb over mixture, then pour in the cocoa mixture. Stir gently to combine. Divide mixture between the two tins. Bake for 25 – 30 minutes or until cooked when tested with a skewer. Cool in tins for 10 minutes then transfer to a wire rack to cool completely.
To make ganache icing, put the thickened cream into a small saucepan over medium heat and bring to a simmer. Remove from heat and stir in the chocolate. Set aside for 5 minutes to allow the chocolate to melt slightly. Stir until smooth. Set aside until mixture comes to a spreadable consistency (this should take about 1-2 minutes).
Put one of the cakes onto a chopping board. Use a large serrated knife to remove the domed top part of the cake and discard. Put the cake, cut side down, on a cake stand. Spoon ½ of the ganache icing on top and spread to cover the top of cake. Spread the remaining ganache icing onto the remaining uncut cake, domed side up, then put on top of the cake on the stand. Serve.