Line base and sides of a 26 x 16cm tin with baking paper. Put white chocolate and condensed milk in a heavy-based pan and stir
over a low heat for 5 minutes or until chocolate is melted and mixture is smooth.
Put biscuits in a food processor and pulse until coarsely chopped. Transfer to a mixing bowl and stir in chocolate mixture. Add almonds, coconut, rind and juice. Stir until well combined and spread evenly over base of prepared tin. Cover with plastic wrap and refrigerate for 1 hour or until set.
Put icing sugar and butter in a bowl and beat with a wooden spoon until creamy. Spread over cooled base and sprinkle with extra coconut. Stand for 10 minutes before cutting into squares.