Preheat your oven to 180C/160C Fan, and line three 8"/20cm round cake tins with parchment paper. Leave to the side for now.
In a bowl/stand mixer, add your butter and sugar, and beat until fluffy.
Add in the eggs and flour, and beat again. Split the mixture into three bowls. It will be about 525g in each bowl to make sure its even.
Add some cooled melted chocolate to one, and mix. Add the coulis and pink food colouring to the other, and mix. And add the vanilla to the final one and mix.
Pour each mix into its own tin, and bake in the oven for 25-30 minutes, or until its baked. A skewer should come out clean!
For the Buttercream!
Beat the unsalted butter (please don't use anything else other than actual unsalted butter) in a bowl until its all smooth. Room temperature butter is best.
Add in the icing sugar and beat again. If the butter was really supple and smooth before adding, this icing sugar should go in easily.
Split the mixture between three bowls, and add the cooled melted chocolate to one, the coulis and pink food colouring to another, and the vanilla to the final and beat again until smooth!
For the Decoration!
Put each buttercream into a bag. Do this in whatever order you like, but I did my chocolate layer, and then my chocolate buttercream, strawberry layer and then my strawberry buttercream, my vanilla layer, and then the vanilla buttercream on top!
With each layer, I just blobbed it on as you can see.
Once each layer is added on, I used the leftover buttercream to add some extra height and decoration to the cake.
Decorate with fresh strawberries, pieces of chocolate, or whatever!
Notes
This recipe will last for 3 days once made
I used Colourmill pink food colouring to get a lovely pink colour, and some strawberry coulis. You can use any red berry coulis if you don't want to make it yourself! It's very important to use GOOD QUALITY food colouring, and not cheap supermarket stuff.
I used dark chocolate because its a better flavour once baked in comparison to milk chocolate. It also gets the colour of the sponge to be darker and look more chocolate like.
You can make a smaller version (two layer) if you like, but obviously you might have to make the sponges swirled in colour if there are only two. Use two thirds of the ingredients and:
300g unsalted butter
300g caster sugar
6 medium eggs
300g self raising flour
75g melted chocolate
40g coulis
I had to trim my sponges down because my oven is a bit off at the moment, but it also showed the pink colour better as coloured sponges can often still look brown on the outside. This is normal.