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. Dust the tin with cocoa powder and shake out the excess.
Heat the oven to 180°C/160℃ fan/350°F/gas mark 4.
Sift together the flour, baking powder, bicarbonate of soda and salt and set aside.
380 g (3 cups + 2 Tablespoons) plain (all-purpose) flour, 1 + ½ teaspoons baking powder, 1 teaspoon bicarbonate of soda (baking soda), ½ teaspoon salt
Place the chopped chocolate in a large bowl and pour over the boiling water. Stir until the chocolate is melted then whisk in the cocoa powder.
125 g (4 ½ oz) dark chocolate, 240 g (1 cup) boiling water, 80 g (¾ cup) cocoa powder (Dutch processed, I used black)
Whisk the oil, yogurt, sugar and vanilla extract into the chocolate mixture.
184 g (200ml/¾ cup + 4 teaspoons)) neutral oil (I use olive), 240 g (1 cup) plain non-dairy yogurt (I use soy), 400 g (2 cups) caster or granulated sugar, 1 Tablespoon vanilla extract
Tip the dry ingredients into the wet and stir with a balloon whisk until smooth. Fold in the chocolate chips.
200 g (7 oz) chocolate chips
Dollop 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 50-60 minutes until a skewer inserted into the centre comes out clean.
Leave the cake to cool in it's tin on a wire rack for 45 minutes before carefully flipping it out of the tin onto a wire rack and leaving it to cool completely. If the top is very domed, use a bread knife to carefully trim it down before turning the cake out.
Once the cake has cooled make the ganache. Place the chopped chocolate in a heat-proof bowl. Heat the milk and butter until it is nearly but not quite boiling then pour it over the chocolate. Leave for a couple of minutes then stir until melted and smooth. Set the ganache aside until it has cooled and thickened slightly then pour over the cake and serve.
100 g (3 ½ oz) dark chocolate, 120 g (½ cup) non dairy milk (I use soya), 20 g (1 ½ Tablespoons) vegan butter