For the Cupcakes

Preheat oven to 180C/350F and line a deep muffin tray with 12 cupcake cases.

Add the butter and chocolate to a small heatproof bowl, place over a saucepan of simmering water. Make sure that the bowl does not touch the water. Heat until all the chocolate has melted. Alternatively, melt in the microwave. Set aside to cool.

In a mixing bowl, sift together the self-raising flour, cocoa powder and baking powder and set aside.

In a large bowl or stand mixer, add the caster sugar, soft brown sugar and eggs. Beat until smooth.

Add cooled melted butter and chocolate, and whisk until well combined.

Add half of the flour mixture, and half of the buttermilk. Mix until just combined.

Add the remaining flour mixture and buttermilk. Mix well until smooth and thick.

Use an ice cream scoop to divide the batter between the cupcake cases, approximately 1 scoop per case.

Bake for 18-20 minutes, or until a toothpick inserted comes out clean. Leave to cool on a wire rack.

For the Buttercream Frosting

In a small bowl, mash the raspberries with a fork until they are soft and beginning to puree.

In a large bowl or stand mixer, beat the butter until soft. Add half of the icing sugar and puree raspberries. Beat until smooth.

Add the remaining icing sugar and raspberries. Beat until smooth.

If the buttercream is too stiff, add a tablespoon of milk and beat until smooth.

To Decorate

With an apple corer hollow the cupcakes and fill with the ready made custard.

Fill a piping bag fitted with a 1cm star nozzle. Hold the piping bag above the cupcake and pipe buttercream so that spreads and floods the cupcake and forms a dome.

Decorate with sprinkles and a fresh raspberry.