Preheat oven to 180 degrees C and grease a 20cmx30cm cake tin and line the base with baking paper.
Sift all the dry ingredients into a large bowl; stir in the apple, meal, eggs, oil and vanilla. When combined pour mixture into the cake tin. Bake for 45 minutes. Turn upside down onto a wire cooling rake and allow to fully cool.
Sift icing sugar and cocoa powder into a bowl, stir in enough apple juice to make a thick icing. Spread evenly over cooled cake.