Preheat the oven to 325F and line 6 holes of a muffin tin with paper cupcake liners.

To make the cupcakes, in a large bowl, mix together the zucchini, egg, sugar, yogurt and vanilla. In a separate bowl, mix together the flour, cocoa powder and baking soda. Pour the wet ingredients into the dry ingredients and stir until the mixture just comes together.

Evenly divide the cupcake batter between the cupcake liners and bake in the preheated oven for 25 minutes, until a toothpick, when inserted into the center, comes out clean. Leave to cool in the muffin tin on a wire rack.

To make the frosting, place the avocado in a medium-size bowl and mash it until there are no lumps. Beat in the cocoa powder and honey until totally combined and the mixture develops a frosting-like consistency. Spoon it on the top of cooled cupcakes and top with sprinkles.