CHOCOLATE LUSTRE CAKE

This cake was inspired by one I saw in a shop window in Le Marais, Paris. The shop itself looked a little down-at-heel, but in the window sat this awe-inspiring cake. I just had to stand and stare ... until dragged away by bored partner. This is the ultimate in chocolate cakes. Its strong cocoa flavour is simply beautiful – only a small slice is required. 

(c) Matt Russell 

Ingredients (serves 12)

  • 250ml water
  • 100g dark chocolate chips
  • 250g salted butter
  • 100g cocoa powder
  • 200g light brown soft sugar
  • 200g golden caster sugar
  • 140g Greek yoghurt
  • 2 eggs
  • 1 tbsp vanilla bean paste or extract
  • 275g plain flour
  • 2 tsp bicarbonate of soda

For the chocolate ganache crumb coat

  • 300ml double cream
  • 200g dark chocolate, chopped  
  • 200g milk chocolate, chopped

To decorate

  • 1 quantity freshly made Mirror Glaze (see recipe here)
  • Edible gold shimmer spray 1 tsp edible gold lustre

Essential equipment

  • 23cm/9-inch springform round cake tin, greased and lined with baking paper
  • 23cm/9-inch round cake card
  • Icing turntable (if possible)
  • Crank-handled palette knife
  • Wire rack with baking paper underneath to catch the drips 

Method

Preheat the oven to 170°C/150°C fan/Gas 3.

Place the water, chocolate chips and butter in a heatproof bowl and set over a saucepan of just simmering water. Allow to warm through until both the chocolate and butter have melted into the water. Remove from the heat and allow to cool, before adding the cocoa powder, sugars and yoghurt. Beat until well incorporated, then add the eggs and vanilla, before sifting over the flour and bicarb and folding those in too.

Pour the batter into the prepared cake tin, and bake for 45 minutes to an hour, or until a skewer inserted into the centre of the cake comes out clean. Allow to cool in the tin until completely cold.

To make the chocolate ganache crumb coat, place the cream in a small saucepan and set over medium heat. Place the chocolate chips in a heatproof bowl. When the cream starts to bubble around the edges, pour over the chocolate chips and allow to warm them for a minute, then with a whisk beat to a smooth, glossy ganache. Allow this to cool – spread on to a tray is best – until it is the consistency of a chocolate spread.

If the cake has domed slightly in the middle, trim it so that it is perfectly flat-topped. Place on to the cake card, and on to an icing turntable if possible. Now ‘mask’ the cake: using the crank- handled palette knife, apply the ganache, spreading it delicately on top of the cake and around the sides. Get it as straight and smooth as possible – the more perfect this layer, the better the mirror glaze will look. I first concentrate on getting the top well covered, and then I manipulate and gently spread the ganache around the sides. Finish it off by neatening the corner where the top meets the sides, and chill for 15 minutes.

Meanwhile, make the mirror glaze as described here. Pass the glaze through a sieve into a cold bowl and allow to cool for a minute – it still needs to be warm so that it is runny, rather than cooled and set. It can be reheated, but do so over a very low heat stirring constantly to avoid burning. 

To finish the cake off, place it – still on the cake card – on to the wire rack. Pour the glaze over the masked cake, easing it down the sides while trying not to disturb the natural flow. To paint the gold strip, in a small ramekin spray plenty of the shimmer spray so that it pools in the bottom, then add the lustre. Mix together, then dip the paintbrush in and gently drag in a line across a segment of the glazed cake. If the mirror glaze needs a little retouching, don’t spread it with a palette knife, simply waft a hairdryer over it, on warm but medium speed, and this should melt the mirror glaze and reset it.

Allow the glaze to set for an hour or two before serving.