Line the bottom of a 20cm spring form tin with baking paper, grease the sides with butter.
Mix the dry ingredients: sift flour, cocoa, baking powder, sugar and salt into a bowl.
In a separate bowl, mix wet ingredients: boiling water, vegetable oil, vinegar, vanilla extract.
Pour the second mixture into the first and stir. Don't overmix, only for as long as it takes for the dry ingredients to become wet. Batter will be lumpy.
Pour the batter into the prepared spring form pan. Bake in the middle of the oven for about 50 minutes or until a toothpick without sticking of the dough.
Remove the finished cake from the oven. Leave on counter for 15 minutes. Then remove the sides of the tin and flip the cake onto a cooling rack. Place a heavy plate on the top of the cake and allow it to cool.
Cut horizontally into 3 equally sized cake 'slices'.
The quality of the resulting cakes are quite unlike traditional homogeneous and springy sponge cake. They are more dense and yet soft and moist.The resulting, separate cake 'slices' should be separated from each other by pieces of baking paper and leave to cool. Carefully - sponge cake is very delicate and breaks easily!!!
While cakes cool, make cream.
Chop the strawberries into small pieces.
Slice the vanilla pod lengthways and scrape the seeds with a knife.
Place the strawberries, sugar, vanilla seeds and balsamic vinegar in a saucepan, bring to a boil and cook over low heat until until the mixture thickens. Cool. Strawberries in balsamic vinegar can be prepared in advance.
Whisk the cream (I used a mixer and it took me to whisk about 8 minutes at high speed). Gently stir in cooled strawberries in balsamic vinegar.
To assemble the cake, cover the two bottom cake layer with cream. Send cake in the refrigerator for about 30 minutes.
Meanwhile, make the ganache.
Once cakes with cream have set, stack them on top of each other and cover with ganache.
Place the chocolate and cream in a bowl and melt in the microwave. If both of these ingredients at room temperature, this should take about 30-40 seconds on full power. You can melt the chocolate in a boiler if you prefer. Mix the melted chocolate with the cream to produce a smooth mixture.
Save a little ganache for decoration. With the rest, cool slightly and spread evenly over top and sides of cake.
Add the ganache set aside to the additional 50ml of cream and decorate the cake with the help of a piping bag.