Method

• 1.
  For the fudge, place the sugar, glucose and 90ml water in a medium saucepan over medium heat. Cook, swirling pan frequently, until sugar dissolves. Simmer, swirling pan frequently, for 6-8 minutes, until sugar turns deep golden brown. Remove from heat and whisk in cream, being careful as it will bubble up and splatter. Return to low heat.
• 2.
  Cook, whisking frequently, for 3-5 minutes, until all crystallised sugar has melted and mixture is smooth and glossy. Add chocolate and whisk until melted and smooth. Transfer to a large heatproof bowl and stir in vanilla. Cover surface directly with plastic wrap and stand at room temperature until completely cool and thick.
• 3.
  Preheat oven to 150°C/130°C fan-forced. Grease 2 x 20cm round cake pans and line base and sides with baking paper.
• 4.
  To make the cakes, place the butter and chocolate in a large heatproof bowl set over a saucepan of simmering water (don't let base of bowl touch the water). Cook for 2-3 minutes, stirring occasionally, until melted and smooth. Remove bowl from pan and immediately add sugar and oil. Stir until combined. Add eggs, one at a time, stirring vigorously between each addition. Add flour and cocoa. Stir until almost combined, then slowly stir in boiling water until combined, smooth and glossy. Divide mixture evenly between prepared pans. Tap base of pans firmly on work surface to release large air bubbles.
• 5.
  Bake for 1 hour 15 minutes or until a skewer inserted in the centres comes out clean, but with a few moist crumbs attached (cake tops will be cracked). Cool in pans for 5 minutes, then invert cakes onto a large baking paper-lined wire rack and cool completely.
• 6.
  Transfer bowl with fudge to the freezer for 15 minutes until firm (a dessert spoon scoop should produce firm peaks that hold). Use handheld electric beaters to whisk until combined and slightly lightened in colour.
• 7.
  Using a large serrated knife, cut each cake in half horizontally to create four layers. Place a cake base, cut-side up, on a serving plate and spread over one-quarter of fudge. Top with a cake top, cut-side down, and spread with one-quarter of fudge. Top with remaining cake base, cut-side up, and spread with one-quarter of fudge. Top with remaining cake top, cut-side down, and spread with remaining fudge. Top with grated chocolate to serve.