Lightly grease a 6cm-deep, 19cm square cake pan. Line base and sides with baking paper, allowing a 2cm overhang on all sides. Place chocolate and butter in a glass or ceramic heatproof bowl. Place over a bowl of simmering water. Cook, stirring occasionally with a metal spoon, for 10 minutes until melted and smooth.

Remove from heat. Break biscuits into pieces. Add biscuit, coconut, pistachios, raisins and cherries. Stir to combine. Spoon into prepared pan. Smooth surface. Cover. Refrigerate overnight or until firm.

Remove from fridge. Stand for 10 minutes. Slice and serve.