- 125g butter, chopped
- 1/2 cup caster sugar
- 1 teaspoon vanilla essence
- 1 1/2 tablespoons cocoa powder
- 1 egg, lightly beaten
- 250g packet arrowroot biscuits, roughly chopped
- 1 tablespoon desiccated coconut
- 2 cups pure icing sugar
- 1/4 cup cocoa powder
- 40g butter, melted
- 2 tablespoons boiling water
Grease and line a 3cm-deep, 16.5cm x 26cm (base) slab pan with baking paper, allowing a 2cm overhang at both long ends. Place butter, sugar, vanilla and cocoa in a saucepan over medium-low heat. Cook, stirring occasionally, for 3 to 4 minutes or until butter melts. Set aside for 5 minutes to cool.
Add egg to chocolate mixture and whisk to combine. Place saucepan over low heat. Cook, whisking constantly, for 10 minutes or until mixture is thick, glossy and smooth. Transfer to a large bowl.
Add biscuits and stir to combine. Spoon into prepared pan. Smooth surface. Cover and refrigerate for 2 to 3 hours or until set.
Make chocolate icing: Sift icing sugar and cocoa together into a bowl. Add butter and boiling water. Stir until smooth. Spread icing over slice. Sprinkle with coconut. Allow icing to set. Slice and serve.