Pre-heat oven to 180°C (160°C fan-forced). Lightly oil the base and sides of 2 x 20cm cake pans. Line the bases with baking paper.
For the cake, place butter and sugar into the large bowl of an electric mixer. Beat until pale and well combined. Add eggs one at a time, ensuring well incorporated prior to adding the next. Add the oil and mix well.
Reduce mixer speed and gradually add the combined flour, cocoa and bi-carb soda, alternating with the buttermilk until smooth. Add food colouring, vinegar and vanilla, mixing until combined. Pour batter evenly between prepared pans and cook for 35-40 minutes, or until an inserted skewer comes out clean. Cool in pan for 10 minutes, before removing to a cake rack to cool completely.
For the shards, place chocolate buttons in a heatproof bowl, over a saucepan of gently simmering water. Heat until melted and smooth. Remove from heat. Pour chocolate onto a large piece of baking paper and spread thinly to approximately a 25 x 20cm rectangle. Sprinkle with coconut and freeze-dried raspberries. Refrigerate until set, then break or cut into shards.
For the cream, combine ½ cup of the cream with the chocolate in a heatproof bowl, over a saucepan of gently simmering water. Heat until melted and smooth. Allow to cool slightly. Beat cream cheese and sugar in the large bowl of an electric mixer until smooth, add remaining cream and continue beating until thickened and smooth. Gradually pour in the cooled chocolate mix, mixing until smooth.
For assembly, trim the cakes with a serrated knife to fit your serving dish. Place one cake into the base of the serving dish, pour over half of the cream mixture and top with half of the berries. Repeat layering, omitting the final layer of berries. These can be added just prior to serving. Cover the trifle and refrigerate for at least 6 hours. Add final berries and decorate with chocolate shards.