Preheat the oven to 160C(320F) fan-forced.

Melt the butter in the microwave in short bursts then place it, the hot water and the cocoa in a small bowl and mix them together.

In a large bowl, place the flour, bicarbonate of soda and sugar and pour over the chocolatey mixture. Whisk it all together then add the eggs, buttermilk and vanilla and whisk them through.

Fill the cupcake pans ⅔ of the way with the batter. Bake the cupcakes for about 20 minutes or until a tester comes out clean.

Transfer the cupcakes to a wire rack to cool.

Ice with your favourite chocolate icing.