Grease the Bundt tin and dust with flour, tip out the excess flour.
Preheat the oven to 160ºC.
Fit the Whisk Tool to the machine.

Add the buttermilk, oil, eggs, vinegar and vanilla bean paste into the 5L Mixer bowl.
Attach the 5L Mixer bowl to the machine.
Mix on speed 5 for 30 seconds.
Remove the bowl from the machine and set aside.

Remove the Whisk Tool, fit the K-Beater.
Add the flour, caster sugar, bicarbonate of soda and sea salt into the 7L Mixer bowl and fit the splashguard.
Attach the 7L Mixer bowl to the machine.
Mix on speed Min for 20-30 seconds until combined.
While the machine is running, gradually transfer the contents of the 5L Mixer bowl into the 7L Mixer bowl.
Mix on speed 1 for 30 seconds.
Mix on speed 3 for 10 seconds.
Divide the mixture evenly between the two Mixer bowls.

Add the cocoa powder and red food colouring into the 7L Mixer bowl and fit the splashguard.
Attach the 7L Mixer bowl to the machine.
Mix on speed 1 for 30-40 seconds until combined with the flour mixture.
Transfer alternate spoonfuls of each mixture into the prepared Bundt tin.
Use a spatula or a handle of a spoon, to marble the two mixtures together in the tin.
Bake at 160ºC for 50-55 minutes until a skewer inserted comes out clean.
Remove from the oven and let cool in the tin for 10 minutes.
Turn out onto a cooling rack and let cool completely.

Retrieve, clean the 5L Mixer bowl and fit the Creaming Beater.
Add the cream cheese into the 5L Mixer bowl.
Attach the 5L Mixer bowl to the machine.
Mix on speed 1 for 20 seconds.
Scrape the sides of the bowl with a spatula.
Add the icing sugar, lemon juice and vanilla extract into the Mixer bowl.
Mix on speed 1 for 1 minute until combined.
Transfer the mixture into a piping bag.
Cut off the end of the piping bag.
Pipe the mixture over the cooled cake.
Alternatively, drizzle the cake with the icing.

Serve