Preheat the oven to 180C / 350F / 160C fan forced. Grease then line two 8 inch cake tins with baking paper.

In a large bowl, sift the flour and cocoa together, then add the sugar, baking powder, baking powder and salt and whisk to combine well.

Make a well in the centre and add all of the wet ingredients - eggs, buttermilk, oil, vanilla, coffee.

Use a handheld beater and mix on low for 90 seconds.

Pour evenly into the 2 prepared baking pans. Place in the oven and cook for around 35-38 minutes or until a toothpick inserted in the centre, comes out with just a crumb or two.

Use a small dish with a flat base to very gently press down on the top on top of each cake just to level them out a little. Don't press down too hard. Cool the cakes in the tins for 10 minutes, then turn out onto wire racks to cool. Cool completely before frosting.

Start by making the chocolate ganache. Place the finely chopped chocolate in a small heatproof dish. Heat the cream in a small saucepan over low heat until its bubbling, then pour it over the chocolate. Give the dish a gentle shake so all the chocolate is submerged. Leave for a few minutes, then stir to a smooth glossy ganache. Make sure the ganache is about room temperature before proceeding.

Beat the butter, cocoa and half the sugar on medium for about 5 minutes or until very light and creamy - scrape down the sides of the bowl every so often.

Add the remaining sugar, salt, vanilla and beat until well combined.

Set aside half of the ganache for the top of the cake. Add the other half to the buttercream mixture and beat until combined and smooth (only about 1 minute).

Spread half the buttercream over the bottom layer of the cake. Place the second layer on top (flattest side up), press down gently to stick them together well. Spread the remaining buttercream over the top.

Transfer the reserved ganache to a squeezee bottle or piping bag and pipe around the edge forcing some of the ganache to drip down. Fill in the centre with the remaining ganache and spread out into an even layer.

Place in the fridge to set a little (it will only need 15 minutes or so) before serving.