Preheat the oven to 180°C/160°C Fan/Gas Mark 4. Grease and line 3 x 7” round cake tins. Combine the soy milk and lemon juice in a small bowl, it should begin to curdle and leave to one side.
Place the flour, Baking Powder, Bicarbonate of Soda, Cocoa Powder and sugar in a bowl and mix together until well combined and make a well in the centre. In a separate bowl mix together the apple sauce and 1 tsp of baking powder.
Pour the oil, Vanilla Extract and apple sauce mixture into the dry ingredients and whisk together until just combined then add the soy milk mixture and whisk into the batter.
Divide the batter equally between the 3 prepared cake tins and bake for 25-30 minutes until risen and a skewer inserted into the centre comes out clean. Leave to cool in the tins for 15 minutes and then transfer to a wire rack to cool completely.
Once the cakes are cool using a serrated knife cut to domed top off one of the cakes and place on a cake board or serving plate.
Set 8 whole oreos a side and crush up the remaining oreo biscuits to a fine crumb. Pop the buttercream into a large bowl and add the oreo crumb and mix together until the oreo crumb is evenly mixed through the buttercream.
Spread a layer of buttercream over the top of the sponge on the serving plate, sandwich another sponge layer on top, continue until all the sponge layers are stacked up and finally spread some more buttercream on top of the cake.
Pop the remaining buttercream into a piping bag fitted with an open star nozzle. Pipe swirls of buttercream on top of the cake.
Pop the coconut milk and chocolate into a bowl and heat in the microwave for 30 seconds and stir, continue to melt in 10 second bursts until you have a lovely smooth melted ganache.
Drip the ganache down the sides of the cake using a spoon or piping bag. Pop the oreos you set aside in between the buttercream swirls.
Ta-dah your cake is now ready to serve, enjoy!