Grease and line a 22cm x 32cm rectangular slice dish with baking paper.
Crush biscuits and place into a bowl.
Add coconut and grated lemon rind.
Mix to combine.
Add melted butter, condensed milk and lemon juice to the biscuit mixture.
Mix thoroughly until well combined.
Press mixture into prepared tin.
Place into fridge.
In a bowl whisk icing sugar, butter and lemon juice until creamy and “frosting like”. If frosting is too thick to spread add a little more lemon juice.
Spread the frosting over the slice, sprinkle with the extra coconut and place back into the fridge and allow to set completely.
Cut into slices.
Store in an airtight container in the fridge for up to one week.