Treat yourself to tea time.
Preheat oven to 180 C (160 C fan-forced). Grease and line a 26 cm x 16cm slice pan with baking paper, extending at long sides for handles.
Combine cake mix, coconut and butter in a large bowl. Press mixture evenly over base of prepared pan. Bake for 15 mins.
Place apple and sour cream in a medium bowl; stir to combine. Spread mixture evenly over warm base; smooth surface. Sprinkle with nutmeg. Bake for 15 mins. Cool to room temperature. Cover with plastic food wrap; chill for 2 hrs or until firm. Cut into squares to serve.