Method

• 1.
  Preheat oven to 155°C/135°C fan-forced.
• 2.
  Lightly spray sides of 2 x 20cm round, 5cm-deep cake pans with cooking oil spray. Line sides with baking paper strips, then line bases with a circle of baking paper.
• 3.
  Put the butter, sugars and oil in the bowl of an electric stand mixer. Using the paddle attachment, cream the ingredients on speed 4 (below medium) for about 4 minutes until the mix is pale malty brown and fluffy. Stop and scrape the bowl side down twice during this process.
• 4.
  Combine the flour, baking powder, bicarb soda and 1/4 tsp fine salt in a bowl.Set aside with a sieve ready. Lightly whisk the milk, chicory powder and vanilla together and set aside. Still on speed 4 (below medium), add eggs in 3 batches, beating well between each addition, scraping down bowl occasionally.
• 5.
  Adding eggs in batches keeps the base fluffy and not looking like curdled soup. So, add some egg, and don’t add the next batch until the mix has re-fluffed.
• 6.
  Remove the bowl from the mixer and push the mix off the paddle into a large, wide mixing bowl. Scrape out remaining mix, sift over half the flour mix and start folding with a sturdy plastic spatula. When it is almost fully incorporated, fold in half the chicory milk. Repeat with the remaining flour mix, then the remaining chicory milk.
• 7.
  Divide batter equally between prepared pans and lightly smooth tops with a spatula. Transfer to oven and bake for 45-50 minutes until cakes have risen. A skewer inserted into the centre should come out clean (internal temperature is 95°C).
• 8.
  To make the ganache, add the chocolate, vanilla and a heaped 1/2 tsp fine salt into a large bowl and set aside. Boil the sugar and water over a high heat until pale golden. Drop the heat and cook until dark brown and pluming with wisps of caramel smoke (190°C).
• 9.
  Remove the saucepan from the heat and add the cream carefully, protecting yourself from spatters. Return the mixture to the heat to melt any hardened caramel. Pour the hot caramel cream over the chocolate and whisk slowly to melt. Cool for 5 minutes, whisking occasionally, then add the butter cubes one by one until dissolved.
• 10.
  Set aside at room temperature to thicken slowly – 2 hours (or accelerate in the fridge), stirring every so often until it reaches a softly spreadable consistency – around 18°C. If re-warming the ganache, it can appear oily on top. No stress, just completely melt to hot, then re-cool, whisking often.
• 11.
  Cool the cakes in their pans on wire racks for 8 minutes, then place a second wire rack or baking tray over the cakes and carefully flip them upside down.
• 12.
  Remove the pans and paper carefully, then gently re-invert onto the wire rack so they are top-side up again. Leave to cool for a few hours (up to overnight, ideally) before assembling.
• 13.
  Chill them if you need extra layering security. While the cakes cool, make the mascarpone whip by gently mixing the cream and mascarpone together until it holds its form – medium peak. Give it a vigorous whip if it is runny.
• 14.
  On the base cake layer, smooth one-third of the mascarpone and drizzle on around 80g of the ganache. Repeat this for the next layers, then place the top layer on.
• 15.
  Smooth enough ganache (you will have spare) thickly over the sides and top, and use the tip of an offset spatula to kick up a little texture on the sides, leaving the top smooth.