Preheat oven the 180°C/ 160°C Fan/Gas Mark 4. Line a 12 hole muffin tray with cupcake cases (we used orange and green). Place the flour, Baking Powder, Bicarbonate of Soda, Cocoa Powder and Sugar in a large bowl and mix together. Make a well in the centre.
In a separate bowl mix together the eggs, milk, oil and Vanilla Extract. Pour the wet mixture into the well in the centre of the dry ingredients and gently begin the fold together. Mix together until all combined and your mixture is smooth.
Divide the mixture evenly between the 12 cupcakes cases. Pop a square of Dark Chocolate into each cupcake, making sure it is pushed into the mixture. Bake the cupcakes for 20-25 minutes until risen and when a skewer is inserted into the centre of a cupcake it comes out clean. Leave to cool in the tin for 10 minutes and then remove from the tins and place on a wire rack to cool completely.
Once your cupcakes have cooled, let’s make the buttercream. Break the Chocolate into a microwavable bowl and melt for 30 seconds and then in 20 second intervals until it has melted.
Pop the butter into a large bowl and beat until softened and lighter in colour. Add the icing sugar in 3 intervals making sure it is mixed through after each addition. Pour in the melted chocolate, vanilla extract and whisk your buttercream until light and fluffy, add a tsp of milk if it is too firm.
Pop your chocolate buttercream into a piping bag fitted with an open star nozzle. Pipe a swirl of buttercream onto each cupcake. Sprinkle over the Chocolatey sprinkle mix. Ta-dah your ready to serve your melt in the middle chocolate cupcakes!