For the Bones- Preheat oven to 120°C. Grease 2 baking trays and line with baking paper.
Beat the egg whites in an electric mixer on low-medium speed until foamy. Add the cream of tartar and continue to beat the whites until they hold soft peaks. Add the sugar a little at a time and continue to beat until the meringue holds stiff peaks. Fold through vanilla essence.
Spoon meringue into a piping bag and snip off the corner. Pipe bone shapes on the baking tray into different sizes, until all the meringue is used up. Bake in the oven for 60 minutes. Allow the bones to cool in the oven with the oven door slightly ajar, then transfer to an airtight container.
For the berry coulis (blood)- To a medium sized saucepan, add the frozen berries, sugar and water. Bring to boil, then lower heat and simmer gently for 15 minutes, stirring often. Transfer to a blender and puree until completely smooth before passing it through a sieve to remove any pulp and seeds. Transfer to a jug and keep refrigerated. It should appear thick and blood like.
For the red velvet cake- Grease and line two 20cm round cake tins with baking paper. Preheat oven to 160°C (fan forced).
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.
Once cool, cut each cake into half so that you have 4 layers for assembly.
For the Swiss Meringue Buttercream- Place egg whites and sugar in the stainless-steel bowl of your stand mixer. Place the bowl over a pan of gently simmering water and gently hand whisk the egg whites until the sugar has dissolved. Ensure that the base of your bowl does not come into direct contact with the water. With a thermometer, check that the egg whites reach 60°C.
Remove the bowl from the heat and place into the mixer stand. Whisk on high until the egg whites hold stiff glossy peaks and the bowl is no longer warm to the touch for about 10 minutes.
Turn the mixer down to low and gradually add the butter, one tablespoon at a time, mixing in well after each addition. Once all the butter is incorporated well and the buttercream is smooth and silky, whisk in the vanilla extract and salt.
For cake filling- In the bowl of an electric mixer or using a handheld mixer, combine the cream, sugar and vanilla. Beat on high for approx. 2 minutes until stiff peaks form.
To assemble- Place a dollop of buttercream in the centre of a cake stand or serving platter and position the first layer of cake. Spread a thin layer of buttercream over the cake layer then in a piping bag filled with buttercream, pipe a ring of buttercream around the edge. Fill the gap inside the ring with jam and top with the whipped cream filling. Repeat this process 3 times until the cake is 4 layers high.
Use the remaining buttercream to cover the entire outside of the cake and position the meringue bones around the cake randomly as well as a few on top. Some broken bones complete the look of this graveyard bone cake.
Drizzle the blood coulis on top or serve it on the side.