Preheat your oven to 160 degrees and line the base and sides of a 22cm round cake tin with baking paper.

Roughly chop six of the Tim Tams into large chunks and set aside until needed.

Chop the butter into 8 pieces of place into a microwave safe bowl. Cook for 1 minute on medium heat or until melted. Set aside to cool slightly.

Sift the cocoa and self raising flour into a large bowl and add the caster sugar, eggs, milk, Tim Tam pieces and melted butter. Mix to combine.

Pour the mixture into the prepared cake tin and place in the oven to bake for 40 minutes or until cooked when tested with a skewer.

Allow the cake to cool in the tin for 15 minutes before carefully turning out onto a wire cooling rack to cool completely.

Once the cake has cooled completely, you can make the chocolate icing by sifting together the cocoa and icing sugar into a medium bowl.

Add the softened butter and pour the boiling water directly over the butter.

Using a small whisk, combine all of the ingredients until the chocolate icing is smooth and is a spreadable consistency. If you find your icing is still a little firm, add an extra teaspoon of boiling water.

Use a large spoon to scoop the icing and place onto your cake. Spread the icing out using a spatula or butter knife until the cake is covered. Roughly chop the remaining five Tim Tams and place on top of the cake to decorate.