Preheat oven to 180?C. Grease, flour and line two 20cm/8 inch cake pans with baking paper.

In a large mixing bowl or stand mixer, beat the butter, sugar and vanilla until light and fluffy.

Add eggs, beating after each addition until incorporated.

In a separate bowl, mix cocoa with hot water a little at a time until it forms a thick paste. Gradually add to the butter mixture.

Add vinegar to milk to sour.

Sift together flour, baking powder and bicarbonate in a separate bowl.

Add the flour to the butter mixture in three lots, alternately with milk, starting and ending with flour. Fold the batter until fully incorporated.

Pour 1/4 of the batter into each of the prepared tins and bake for 23 minutes. Allow to cool for 10-15 minutes in the tins, then turn out to cool on a cooling rack.

Bake the remaining batter in the re-prepared tins.

For the salted caramel, add sugars to a heavy bottomed saucepan, stirring occasionally, until the sugars melt and become smooth.

Add butter and whisk until melted and stirred through.

Remove from heat and slowly pour in heavy cream. Return to heat and boil for 1 minute. Remove from heat and stir in salt. Allow to cool.

For dark chocolate ganache, melt chocolate in a large microwave-proof bowl in 30 second intervals.

Once melted, add cream and stir until smooth. Allow to cool slightly.

For salted caramel buttercream, beat butter until light, fluffy, and paler in color.

Sift in icing sugar and beat well. Add salted caramel and beat until well combined.

Refrigerate for 10-15 minutes.

To assemble, place one chocolate fudge cake layer on a baking paper or cake plate.

Pipe a border of large 'kisses' around the outside of the cake with buttercream.

Fill the interior with buttercream and spoon on a generous amount of salted caramel sauce. Repeat with all layers, alternating salted caramel sauce and dark chocolate ganache.

Top with more piped kisses and pour over ganache, encouraging it to drip over the sides.

Serve and enjoy!