Preheat oven to 170C/150C fan forced. Grease three 18cm (base size) round cake pans. Line bases and sides with baking paper.

Use electric beaters to beat butter, sugar and vanilla in a bowl until pale and creamy. Add eggs, 1 at a time, beating well after each addition until combined. Add flour and milk, in alternating batches, beginning and ending with flour, until just combined. Divide among prepared pans and smooth surface. Bake for 30 minutes or until a skewer inserted into centre comes out clean. Set aside in pans for 5 minutes before transferring to a wire rack to cool completely.

Meanwhile, make the buttercream. Use a whisk to combine the egg whites and sugar in a heatproof bowl. Place over a saucepan of simmering water (make sure bowl doesn’t touch water). Cook, stirring often with a whisk, for 3-5 minutes or until hot to touch. Transfer mixture to a stand mixer with whisk attachment. Whisk on high speed for 10 minutes or until almost room temperature. Switch to the paddle attachment. On low speed gradually add butter, beating well after each addition until smooth and creamy. Beat in vanilla and pinch of table salt until combined. Transfer 2 cupfuls to a bowl. Fold through berries.

Line a tray with baking paper. Dip tops of cones in dark chocolate. Transfer to prepared tray. Place in freezer for 5-10 minutes or until set.

Trim and level top of cakes. Use a little plain buttercream to secure 1 cake, top-side up, to a cake board. Spoon 1 cupful plain buttercream into a piping bag fitted with a 1cm plain nozzle. Pipe a ring around top edge of cake. Cover middle with half the berry buttercream. Repeat layering with another cake, plain buttercream and remaining berry buttercream. Top with final cake, top-side down. Spread a thin layer of plain buttercream over side and top of cake (this is called a crumb coat). Place in fridge for 20 minutes. Place half remaining plain buttercream in a bowl. Tint with colouring. Transfer to a piping bag fitted with a 1cm plain nozzle. Spoon remaining into a piping bag fitted with a 1cm plain nozzle.

Pipe rings of buttercream, in alternating colours, around the side of the cake, starting from the base and working up. Use an offset palette knife or cake scraper to smooth and create stripes. Switch the nozzle on the pink buttercream to a 1cm fluted nozzle.

Gently press cones into side of cake. Pipe swirls of buttercream, in alternating colours, on top of cones. Tint white choc with colouring. Top plain swirls with pink choc, Crunch and extra berries. Press Crunch around cake base. Just before serving, top pink swirls with fairy floss.