Method

• 1.
  Preheat oven to 180°C/160°C fan-forced. Grease base and side of a 20cm round, 7cm-deep springform cake pan with extra butter and line with baking paper.
• 2.
  Place the butter, chocolate, cinnamon and nutmeg in a large heatproof bowl. Place the bowl over a pan of simmering water (don’t let base of bowl touch the water). Cook, stirring constantly, until melted, combined and smooth. Remove bowl from pan and set aside to cool.
• 3.
  In a separate large bowl, whisk the egg yolks with half the sugar, the orange zest and cocoa powder. Whisk until yolks are thick and mixture is paler in colour, about 2-3 minutes. Add the cooled chocolate mixture and whisk until smooth.
• 4.
  Place egg whites in a stand mixer fitted with the whisk attachment. Whisk until frothy then, with motor running, add in the remaining sugar, 1 tbs at a time. Once you’ve added in all the sugar and the whites are firm and glossy, fold about a quarter of the whites into the chocolate mixture. The first batch of egg whites is to loosen the mixture, so you don’t need to be too careful about knocking out air.
• 5.
  Gently fold in the rest of the egg whites, then pour batter into prepared pan. Bake for 40-45 minutes until cake looks risen and edges are set. There should still be a little wobble in the middle. Transfer cake in pan to a wire rack and cool completely in pan.
• 6.
  For the oranges, slice top and bottom off each orange. Sit them upright and use a small, sharp knife to slice away the skin and pith, following the curve of the fruit. Cut between the membranes to remove the segments. Toss the orange segments with the sugar, liqueur or juice, cinnamon stick and star anise in a medium bowl. Cover and chill for 1 hour, stirring occasionally, to macerate.
• 7.
  Serve slices of cake with orange segments and syrup, creme fraiche and finely grated extra dark chocolate.