In a large bowl, whisk the dry ingredients together.
In a separate bowl, whisk together the milk, vegetable oil vanilla, eggs and melted dark chocolate.
Pour the wet ingredients into the dry and then stir in until almost fully combined then pour in the boiling water and mix until a smooth batter forms.
Grease and line a rectangular cake pan with parchment paper (or use any cake pans of your choice - this recipe will make two round layers or one sheet cake). Pour the cake batter into the prepared pan then place in the oven.
Allow to bake for 30-40 minute or until a toothpick inserted comes out clean.
Remove from the oven and allow to cool completely before removing from the pan.
Beat the butter and sugar for 5 minutes on medium speed until light and fluffy.
Scrape the bowl down with a spatula a few times while beating. Add the cocoa powder and beat in.
Add the melted chocolate and cream and beat until smooth and creamy. Top the cooled cake with the chocolate frosting and spread with a spatula or spoon.