Grease a 20cm x 30cm sponge roll tin and line with baking paper.
In a medium-large saucepan heat the butter, Chelsea Soft Brown Sugar and condensed milk until the butter has melted. Do not boil.
Remove from the heat and add chopped apricots and crushed biscuits. Mix well. Press mixture into the prepared tin. Refrigerate while you make the icing.
Beat butter until pale and fluffy. Add Chelsea Icing Sugar and lemon zest, then beat in sufficient lemon juice and hot water so that you have a light, fluffy mixture. Spread over the slice and sprinkle with coconut. Set in refrigerator before cutting into squares.