Preheat the oven to 180°C/160℃ fan/350℉/gas mark 4. Place a 10-12 cup bundt tin in the fridge for 15 minutes then thoroughly brush it with melted vegan butter making sure that you get right into all of the nooks and crannies.
Sift together the flour, cornflour, cocoa powder, baking powder, bicarbonate of soda and salt in a large bowl.
380 g (3 cups + 2 ½ Tablespoons) plain (all-purpose) flour, 40 g (⅓ cup) cornflour (cornstarch), 20 g (¼ cup) cocoa powder, 1 teaspoon baking powder, 1 teaspoon bicarbonate of soda (baking soda), ½ teaspoon salt
Add the sugar, melted butter, oil, milk, yogurt, vanilla extract and vinegar. Stir with a balloon whisk until it is just starting to combine but is still lumpy.
300 g (1 ½ cups) caster or granulated sugar, 120 g (½ cup) vegan block butter, 110 g (½ cup) neutral oil (olive/sunflower/canola/avocado)*, 250 g (1 cup) unsweetened non-dairy milk (I use soy), 160 g (⅔ cup) plain non-dairy yogurt (I use Greek style soy), 1 Tablespoon vanilla extract, 2 Tablespoons white wine or cider vinegar
Add a couple of drops of food colouring and continue to stir until no dry lumps remain, adding more food colouring as needed to achieve a deep red colour.
about ½ teaspoon red gel food colouring
Pour the batter into the prepared tin and spread it level. Tap the tin on the worktop a couple of times to get rid of any air bubbles then bake for 45-50 minutes until a skewer inserted into the centre comes out clean.
Leave the cake to cool in the tin on a wire rack for 20 minutes before carefully flipping it out of the tin onto a wire rack and leaving it to cool completely.