Preheat oven to 160C. Grease and line two 20 cm round tins. In a large bowl, add the flour, hazelnut meal, baking powder and salt. Stir together to combine and ensure that no big lumps of hazelnut meal remain. In a separate bowl, using an electric mixer, cream the butter, sugar and vanilla until light and fluffy. Add the eggs one at a time, beating well after each addition. Add half of the combined dry ingredients to the creamed mixture and stir until combined. Add half of the buttermilk and stir until combined. Repeat with remaining dry ingredients, followed by remaining buttermilk. Divide the mixture evenly between the two prepared tins and smooth out. Bake in preheated oven for approximately 35-40 minutes, until a skewer inserted into the middle of one of the cakes comes out clean. Cool in tins for 10 minutes before transferring to wire racks to cool completely.

To make the buttercream, melt the dark chocolate dotties in short 10 second bursts in the microwave, stirring at each interval until all the chocolate is melted and smooth. Set aside to cool slightly. In a separate bowl, whisk the icing sugar and cocoa together until combined.

In another separate bowl, beat butter and vanilla extract with electric mixer until pale. Add half of the icing sugar and cocoa powder mixture and beat until combined, then add one tablespoon of the cream and beat until combined. Repeat with remaining icing sugar and cocoa followed by one tablespoon cream. Add cooled melted chocolate and beat until combined and mixture is a smooth, pipeable consistency. If the mixture is still too firm, add a little more cream, or milk if you prefer, and beat to combine, until you reach the right consistency.