Preheat oven to 180°C and line the base of two 23cm springform round cake tins with baking paper.
Using a stand mixer fitted with the paddle attachment, beat butter, sugar and salt on medium speed until light and fluffy. Then add the eggs one at a time, beating well after each addition.
In a medium size bowl combine the sifted the flour, cocoa and baking powder. Then add the egg mixture in two batches, alternating with the melted chocolate, creme fraiche and milk. Beat using a hand whisk until the cake batter is smooth.
Divide the cake batter evenly amongst the two cake tins and bake for 45 minutes or until a skewer inserted into the middle of the cake comes out with moist crumbs. Allow the cakes to cool in the cake tins for 15 minutes before transferring to a wire rack to cool completely.
Melt the white chocolate in a small bowl over a saucepan of barely simmering water, stirring until smooth. Remove from the heat and whisk in the creme fraiche before refrigerating for 1-1½ hours until beginning to firm.
Using the stand mixer fitted with the whisk attachment, whisk the ganache mixture until soft peaks form. Then stand at room mixture until ready for use.
Stir the ingredients in a saucepan over medium heat until the sugar dissolves. Then bring the mixture to the boil and cook for 4-5 minutes until slightly thickened. Remove from the heat and allow to cool to room temperature.
In a saucepan over medium heat, bring cream to the boil. Then remove from the heat and add the chocolate and let it stand (without stirring) for 5 minutes before stirring until smooth. Stir in creme fraiche until just combine and set aside at room temperature.
Trim the tops of each cake flat if necessary then halve each cake horizontally. Place a cake half on a cake board and spread a third of the cherry jam followed by the white chocolate ganache. Then add second cake half and repeat layering. Repeat for the third cake half and finish layering by topping with the final cake half.
Make sure the chocolate icing has began to thicken and cooled to room temperature before spreading over the top and sides of the cake. You may need to apply several layers of chocolate icing to cover up the sides of the cake. Once the cake has been covered in the icing refrigerate until firm (Approx 1-2 hours). Then decorate the top of the cake with left over cherries and chocolate shavings before serving.