Instructions

1. Preheat oven to 180 C (350 F) standard / 160 C (320 F) fan-forced. Line a 12 hole muffin tin with cupcake liners.
2. In a large mixing bowl, add flour, cocoa powder, baking soda, baking powder and then add the sugars. Pop the butter into the microwave for a short burst, 10 seconds or so at a time, until it becomes very soft but just before it is completely melted. Give it a stir with a fork to eliminate any lumps.
3.  In a separate mixing bowl, add eggs, vanilla and butter and whisk together until smooth. Then add the wet mixture into the dry mixture, along with the buttermilk and gently fold until just combined. Fold in chocolate chips.
4. Spoon the mixture into the cupcake liners and pop into the oven. Bake for 18-20 minutes or until just cooked through. Set cakes out onto a wire rack and leave to cool completely.
5. To make the frosting, place butter in a large mixing bowl and beat with an electric mixer on medium speed for a couple of minutes until pale and creamy. Meanwhile melt the chocolate in a microwave, stirring in between 20 second bursts, until just melted and set aside to cool a little.
6. Once the butter is very pale and creamy, add half of the sugar and one tablespoon of milk and beat on low until the sugar is incorporated. Then, add the rest of the sugar and the milk, and again beat on slow until the sugar is incorporated before turning up to medium for another minute or so.
7. Next, add in your melted chocolate to the buttercream mixture, ensuring the chocolate is still smooth and melted but is not warm. Beat until the chocolate is completely mixed through. Transfer your frosting to a piping bag fitted with a large circular tip. Pipe swirls onto each cupcake. Add sprinkles on top.