Method
1. Pre-heat oven - 179°C
2. Line 2 clean springform pans with parchment paper
3. Add butter and caster sugar to a clean stand mixer bowl
4. Cream until light and fluffy
5. Add egg to the batter one by one and continue mixing
6. Scrape thoroughly and continue
7. Mix in vanilla extract to the batter
8. Add all purpose flour and cocoa powder to a clean medium bowl
9. Whisk briefly until combined then set aside
10. Add buttermilk to a clean glass measuring cup
11. Mix dry ingredients into batter bit by bit
12. Mix milk mixture into batter until smooth
13. Mix in food coloring to the batter
14. Add baking soda and white wine vinegar to a clean small bowl
15. Mix briefly until combined
16. Stir mixture into batter
17. Pour batter into 2 springform pans
18. Bake until springy to touch - 20 min, 179°C
19. Add egg white, caster sugar, vanilla extract and cream of tartar to a clean medium glass bowl
20. Set in double boiler
21. Whisk until sugar has dissolved and turn off heat
22. Beat until glossy then set aside - 6 min
23. Add icing sugar and food coloring to a clean small bowl
24. Add water to the liquid bit by bit
25. Stir until mixture comes together then set aside
26. Transfer springform pans onto cooling rack
27. Let cool completely
28. Assemble
29. Drizzle liquid with content of springform pans