Serves: 12 cakes
To make the cupcakes:
Preheat the oven to 180C/Gas 4. Line the large muffin tins with large paper cupcake liners.
Put the butter, coffee, water, and cocoa in a microwave-safe bowl, cover with plastic wrap, and microwave on HIGH until the butter melts, about 2 minutes. Whisk to combine.
Meanwhile, whisk the flour, granulated sugar, baking powder, bicarbonate of soda and salt in a large bowl. Beat the sour cream with the egg and vanilla in a small bowl. Whisk the hot cocoa mixture into the dry ingredients. Stir in the sour cream mixture just to combine;
Divide the batter evenly between the prepared muffin tins, filling each paper case about 3/4 of the way full (about 160ml per cupcake). Bake the cupcakes until a toothpick inserted in the center of the cake comes out clean, about 30 minutes.
Cool the cupcakes completely in the tin on a rack. Remove from the paper cases and return the cakes to the rack.
For the glaze:
Put the chocolate in a medium bowl. Bring the coconut milk and golden syrup to a boil, stirring constantly, then pour it over the chocolate. Let the mixture stand for 10 minutes, then stir until smooth.
Spread one tablespoon of the warm glaze evenly over each cake, then scatter the coconut chips or shredded coconut over the top.
Cook's Note: We prefer Dutch-process cocoa here over natural cocoa for its fuller, deeper flavour.