01 - Line an 8-inch square baking tin with parchment paper, allowing overhang for easy removal.
02 - Crush biscuits into fine crumbs using a food processor or rolling pin. Mix with melted butter, desiccated coconut, and sweetened condensed milk until well combined. Press mixture firmly into the base of the prepared tin and refrigerate.
03 - Beat powdered sugar, softened butter, milk, peppermint extract, and optional green food coloring until smooth and spreadable.
04 - Spread peppermint filling evenly over chilled base and refrigerate for 20 to 30 minutes until set.
05 - Melt dark chocolate and butter together gently over simmering water or in the microwave, stirring until smooth.
06 - Pour chocolate topping over peppermint layer, tilting the tin to evenly cover. Refrigerate for 1 hour until fully set.
07 - Cut into 16 squares using a warm, sharp knife. Serve chilled.