Method

• 1.
  Preheat oven to 200°C/180ºC fan-forced. Grease base and sides of a 38cm x 26cm, 3cm-deep rectangle baking tray and line with baking paper.
• 2.
  For the sponge, place chocolate, cocoa, oil, 1/2 tsp fine salt and 200ml water in a medium saucepan. Bring to a simmer over medium heat, whisking constantly until smooth and starting to simmer. Scrape into a large bowl. Set aside until lukewarm.
• 3.
  Place eggs and sugar in a stand mixer fitted with the whisk attachment and whisk for 8 minutes on medium-high speed until thick and tripled in volume. Meanwhile, sift flour and cornflour together 3 times.
• 4.
  Add egg mixture to chocolate mixture and gently fold until combined. Sift over half the flour mixture, gently fold until almost all incorporated, then sift over the remainder. Gently fold until there are no floury or chocolatey streaks.
• 5.
  Scrape into prepared tray and smooth out to level. Bake for 18 minutes until top is dry and sponge is springy. Invert onto a cooling rack, carefully lift off tray, peel away paper, then re-invert and cool fully.
• 6.
  Meanwhile, for the filling, drain apricots over a medium saucepan and add peel, juice and sugar to the syrup. Bring to the boil, stirring until sugar dissolves. Gently boil for 10 minutes until a thick syrup. Next, thickly slice apricots, add to syrup and simmer for 5 minutes to soften. Set aside to cool. Reserve peel to decorate. To assemble, cut sides of sponge to straighten, if needed. With the long edge facing you, cut three equal pieces. Place first piece back onto cooling rack. Brush with 1 tbs liqueur and gently spoon over half the apricot mixture, lightly pressing apricots into sponge with the back of the spoon. Top with another piece of sponge and repeat with liqueur and apricot. Brush remaining sponge with liqueur and place, liqueur-side down, to finish. Adjust sponge stacks to align pieces and press lightly. Brush crumbs from side, cover with plastic wrap and chill overnight.
• 7.
  Mix jam with 1 tbs boiling water and brush top and sides of cake with jam.
• 8.
  For the ganache, place the chocolate in a medium heatproof bowl over a saucepan of simmering water (don’t let base of bowl touch the water) and stir until melted. Remove from heat and stir in the cream until combined, then stir in the syrup until combined. With cake still on the rack and placed over a baking tray to catch any dripping chocolate, pour ganache slowly over the cake, guiding ganache to fall down the sides. Smooth top and sides with a metal spatula to evenly coat, and set aside to set. While ganache sets, melt dark chocolate in a microwave-safe bowl in 30-second bursts and smooth thinly onto a sheet of baking paper. Cover with a second piece of baking paper and roll up to form a 2cm-diameter cylinder. Freeze for 30 minutes, then unroll – the chocolate will break into shards.
• 9.
  Once ganache has set, lift cake carefully onto a serving plate using an egg lifter. Top with chocolate shards, dust with cocoa and top with reserved candied peel. Cut with a hot damp knife.