Pre-heat oven to 180C. Sift the cake dry ingredients together. I use my food processor for this cake. Because the recipe required the butter to pulse it into dry crumbs. I don't think my mixer could do crumbs like that but this is a personal preference.
Blend the semi solid butter into the dry ingredients until the mix looks like wet crumbs.
Add the wet ingredients; the milk, coffee and vanilla. Whisk till mixed, at the end, add in the two beaten eggs and give it another pulse. Scrape the sides and bottom to make sure there are no chunky bit.
Give it a final mix.
Divide batter to two 8 inch pans that have been greased and lined with baking paper.
Bake for 30 mins to 45 mins depending on your oven.
Make the frosting in the meantime.
Pour chocolate and cream into a heatproof bowl. Place over a saucepan of boiling water.
Let it melt together.
Pour sour cream into a cup. Add the salt and vanilla. Mix it together.
When the chocolate and cream had melted together into a smooth consistency, mix in the sour cream.
Chill for about 30 mins to 45 mins before using.
When cakes are ready, cool in the pan for 30 mins before turning it out on a rack.
The cakes have to be completely cool before frosting.
Spread the frosting on top of the first half. Place the second half face side down with the flat side facing top.
Dollop a huge amount of frosting on the top and spread it out letting it fall to the sides. Cover the sides with the excess frosting.
Place blackberries on top.
If you had chilled the cake, take it out for 30 mins before eating else it would be too hard to slice into.