Heat your oven to 350°F/ 180°C/160°C Fan/Gas Mark 4
Mix together your almond milk and cider vinegar and set aside to curdle.
Mix together your coffee and just boiled water and set aside to cool.
Mix together your sugars and rub out any large lumps of brown sugar between your fingers.
Sift together your flour, cocoa, baking powder and salt into your mixing bowl.
Gently mix in your sugars on a low speed.
Add your milk mixture, oil and vanilla extract and beat on a high/medium setting for about 10 seconds until incorporated. Scrape down with your spatula to ensure everything is mixed and then mix again for 10 seconds.
Set aside half of your mixture into another bowl.
Fold in your red food colouring into the remaining mixture with a metal spoon. Add just enough to turn it bright red, probably about ½ teaspoon depending on the brand you are using.
Using a separate teaspoons for both bowls of cake mixture first add 2 teaspoons of the chocolate mixture to each cavity in the Bundt tin.
Repeat with red mixture on the opposite side of the cavity and so on.
Take your skewer and draw it gently through the mixture to create a marbled effect, don't do it too much otherwise you will just mix it in too much and lose the effect.
Bake in your oven for 20-25 minutes. The Bundt cakes will spring back when touched when they are ready.
Remove from your oven and leave too cool in the tin for 5 minutes.
Gently remove each one from your Bundt tin and cool on a cooling rack.