1. Preheat the oven to 350°F (180°C). Line a muffin tin with 12 paper liners and set aside.

2. Melt the butter and chocolate in a small bowl – either over a saucepan with simmering water or in the microwave. Stir well, set aside, and let cool down for a while.

3. Add both sugars, the eggs, and the vanilla extract to a large bowl and mix until very light and fluffy. Add the cooled chocolate mixture and stir to combine. In a separate bowl mix flour with cocoa powder, baking powder, baking soda, and salt – add to the large bowl in two batches, alternating with the buttermilk. Stir until just combined. The batter will be quite thick.

4. Fill the batter into the prepared paper liners and bake the cupcakes for about 16-18 minutes or until a toothpick inserted into the center of a cupcake comes out clean. Take the cupcakes out of the oven and let them cool down completely.

5. Mash the raspberries for the raspberry sauce with a fork, then pass them through a fine-mesh sieve to remove the seeds. Add some confectioners’ sugar and mix well. The sauce should not be too runny, if necessary, add a little more confectioners’ sugar to thicken the sauce further. Set aside.

6. For the buttercream, add egg whites and sugar to a heatproof bowl over a saucepan with simmering water. Heat up the mixture while stirring constantly until the sugar has dissolved completely and its temperature has reached 160°F (71°C). If you don’t have a thermometer to hand, simply test the mixture by hand. If you rub the mixture between your fingers, you should no longer feel any sugar grains, then you know the mixture is ready for the next step. Once the temperature/texture is reached, transfer the mixture to the bowl of a food processor and whisk until it is white, fluffy, and cool – this can take up to 10 minutes.

7. Once the egg white mixture (meringue) has cooled enough, gradually add the butter in small pieces and continue mixing – the aim here is to slowly mix the butter with the meringue to create a smooth buttercream. When everything has the same temperature, this works well. If there are still pieces of butter visible, the butter was too cold. If the mixture looks soupy, the meringue was still a bit too warm and has melted some butter. There is a solution to both problems here. If the pieces of butter do not dissolve, simply warm the entire buttercream slightly and then whisk it again. If the meringue was too warm and the butter has melted, simply place the whole bowl in the fridge and whisk the buttercream again after a few minutes – this should solve any texture problems. When everything looks nice and smooth, add the vanilla extract and mix in.

8. Remove about 1/3 of the buttercream from the bowl and mix with a few drops of yellow food coloring. Add two tablespoons of the raspberry sauce and a few drops of red food coloring to the rest of the buttercream and mix well.

9. Pipe some red buttercream onto each cupcake as a base (using a large round piping tip) and drizzle it with some of the remaining raspberry sauce. To finish, pipe a dab of yellow buttercream on top using a large star tip. Chill until ready to serve.