Grease a six centimetre deep, eighteen centimetre diameter round spring-form cake pan and line base and sides with baking paper.
Place butter, chocolate, cocoa powder and orange juice into a medium saucepan over a low heat. Cook, stirring constantly for 2 to 3 minutes or until melted and combined.
Remove from heat, transfer to a bowl and allow to cool slightly.
Using an electric mixer, beat the egg yolks and sugar for 5 minutes or until thick and set aside. Using a clean bowl with the electric mixer, beat the egg whites until soft peaks form.
Add the chocolate mixture and almond meal to egg yolk mixture and stir to combine. Using a large metal spoon, gently fold half of the egg whites into the chocolate mixture, then repeat with remaining egg whites.
Pour the mixture into the prepared pan and bake for 40 to 45 minutes or until an inserted skewer comes out with moist crumbs but not sticky. Use the skewer to make small holes through the cake and pour over the warmed Bitter Orange Syrup.
Cool cake completely in pan. Dust with cocoa and top with slices of Bitter Oranges in Spiced Verjuice.