Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4, and grease and line two 18cm cake tins
In a large mixing bowl, stir together the plain flour, light brown sugar, cocoa powder, bicarbonate of soda and baking powder
In a large jug or another mixing bowl, whisk together the vegan condensed milk alternative, unsweetened plant milk, vegetable oil and vanilla extract
Pour the wet ingredients into the dry, whisking to combine them as you pour
Once they are mixed together, divide the mixture between the cake tins, use scales for accuracy
Bake them for 25-30 minutes or until a skewer inserted in the middle comes out clean. Leave them to fully cool in the tins
To make the frosting, firstly break the vegan dark chocolate into chunks and place into a microwave safe bowl. Microwave for 30 seconds, then stir, then microwave in 10 second blasts, stirring between each one, until it has fully melted. Leave to cool for 10 minutes
Use an electric mixer to whisk together the dairy free butter and the vegan condensed milk alternative until smooth
Then stir in the melted vegan dark chocolate and vanilla extract. Then add the icing sugar and cocoa powder and beat until smooth. If the frosting is too thick, you can add some plant milk to loosen it. Or if it is too lose, you can add extra icing sugar to thicken it
Put one of the sponges on your plate or cake stand (you may wish to level it off with a knife if it has domed too much) and pipe or spread half of the frosting onto it
Add the other sponge on top and pipe or spread the remaining frosting on top
Serve immediately. Leftovers will keep in an airtight container in a cool place for 2-3 days