Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4, and grease and line two 8" cake tins (that are at least 2" deep)
Make both the sponges at the same time in different bowls
For both sponges mix the butter and caster sugar together, ideally using an electric mixer
For the pink sponge add the eggs and vanilla extract, and whisk well
For the chocolate sponge add the eggs and milk, and whisk well
For the pink sponge, add the self raising flour and mix in, then add the pink food colouring until you get the desired shade
For the chocolate sponge, add the self raising flour, cocoa powder and milk and mix in
Add the batter to the cake tins in alternate spoonfuls, place each spoonful on top of the previous one. Continue until all of the batter is used up. The batter will spread out and fill the tin as you add it, but you can give them a little shake if needed to encourage it
Bake them for 30 minutes or until a skewer inserted in the middle comes out clean. Leave them to fully cool either in the tins or on cooling racks
To make the chocolate buttercream mix the butter, cocoa powder and icing sugar together. Once it starts to come together add the milk and mix until smooth. I use my electric hand whisk to do this but you can also do it by hand with a spoon
If the cakes have domed on top, level them off with a cake leveller
Put one of the sponges on your cake stand and pipe a circle of buttercream blobs around the edge using a piping bag fitted with a round nozzle, then fill the centre with raspberry jam. You can fill the middle with just the raspberry jam too if you prefer
Add the second sponge, and spread chocolate buttercream all over the top
Pipe another circle of chocolate buttercream blobs around the edge and top them with the fresh raspberries
Use a vegetable peeler to shave dark chocolate into the centre, or use shop bought chocolate curls or sprinkles
Leftovers will keep in an airtight container for 2-3 days