Pre-heat oven to 180C (160C fan-forced). Line 16 x 1/3 cup capacity muffin pans with paper cases.
Using electric beaters, cream together the butter and sugar. Add eggs one at a time until well incorporated. Add vanilla.
Combine the flours, cocoa, baking powder and bi-carb. Gradually add to the butter mixture, alternating with the milk until mixture is smooth.
Spoon between paper cases and bake for 16-18 minutes, or until they spring back when pressed. Allow to cool on a wire rack.
For frosting: Beat together the avocadoes until smooth. Add cocoa and maple mixing well. Refrigerate until required. When serving, pipe frosting over cooled cupcakes.