Heat the oven to 180C/Fan160C/gas 4. Line 2 x deep 20cm springform cake tins with baking paper, or use a 900ml loaf tin, or 2 x 7” sphere moulds.
Stir together the flour and cocoa in a bowl. Melt the chocolate, sugar and butter with 100ml water in a pan until smooth, then leave to cool.
Once cooled, transfer to a mixing bowl and whisk in the eggs one by one until combined, followed by the vanilla extract. Slowly whisk the wet ingredients into the dry ingredients and stir until fully combined.
Pour into the prepared tin/s and bake for 30 minutes at 180c/160c fan/gas4, then reduce the heat to 160c/140c fan/gas 3 for 15 minutes, or until cooked through. Leave to cool.
To assemble: Sandwich – mix the orange marmalade with the brandy and spread on one half of the cake, then top with the other half. Tin – cut through the loaf lengthways and spread the bottom half with the marmalade and top with the other half, the same way with the sphere.
For the ganache, heat the cream until almost at boiling point, remove from the heat, add half the chocolate and stir, then add the rest after 30 seconds. Set aside to cool and thicken.
For the topping: Place the sugar into a saucepan, add 100ml of the juice from the orange and boil until slightly thickened. Cut the orange strips into thick julienne strips and cook for 5 minutes, turn off the heat and stir in the brandy and leave to cool.
Once the ganache is spreadable, pile on top of the centre of the cake and ease over the top and around the sides to seal the cake in completely. I use a spatula dipped into hot water to help ease it all over.
Use tongs to remove the strips of orange from the syrup and create a garland on the outside of a round cake; along the centre of a loaf cake; in the centre and trailing like it was dripping down a little. Sprinkle over the pistachios, spray with gold and add a trinket should you wish.