- 200g Arnott's Marie Biscuits
- 200g walnuts, coarsely chopped
- 125g butter
- 215g (1 cup) caster sugar
- 1 egg, lightly whisked
- 1 tablespoon cocoa powder
- 1 teaspoon vanilla extract
- 300g (2 cups) pure icing sugar, sifted
- 50g (1/2 cup) cocoa powder
- 60ml (1/4 cup) hot water
- 1Line a 16 x 26cm (base measurement) slice pan with baking paper, allowing the 2 long sides to overhang. Place the biscuits in a large sealable plastic bag. Use a rolling pin to pound until well crushed (about 1cm pieces). Transfer to a bowl. Stir in the walnuts.
- 2Heat the butter and sugar in a saucepan over a low heat, stirring for 5 minutes or until the mixture is well combined and smooth. Remove from the heat. Stir in the egg until well combined, then stir in the cocoa and vanilla.
- 3Pour the chocolate mixture over the biscuit mixture and stir until well combined. Spoon into the lined pan. Use the back of a spoon to press firmly into the pan. Place in the fridge for 2 hours or until firm.
- 4To make the icing, stir the icing sugar, cocoa and hot water in a small saucepan over low heat until melted. Cook, stirring constantly for 2 minutes or until glossy. Quickly pour over the slice to cover. Place in the fridge for 1 hour to set. Cut slice into squares or rectangles.