Note: I didn't have 9" pans so used 8" ones. It worked, but I cooked it a lot longer and it was still undercooked.
Two 9" round spring-form pans, greased and lined with baking parchment
160°C | 315°F
70-75 minutes (or until a toothpick comes out clean)
1½Tbsp
Distilled White Vinegar
Mix together and set aside to curdle.
2½C+2Tbsp (525g)
Caster Sugar
Mix in your largest bowl.
1C+2Tbsp (83g)
Cocoa Powder
Sift in.
3tsp (14g)
Bicarbonate of Soda
1½tsp
Baking Powder
Add and whisk well (should be all one colour).
1½C (320g)
Oil (vegetable / sunflower)
Add these and the curdled milk, whick until combined.
1½tsp
Instant Espresso Powder
Mix together to make coffee.
1½C
Boiling Water
Gradually whisk into cake mixture.
90g
Chocolate (dark 70%)
Grate into a bowl. Chop up any last bits. Set aside.
1C+2Tbsp (170g)
Corn Flour
Whisk together in a medium saucepan.
¾C (65g)
Cocoa Powder
Sift in and whisk well (should be all one colour).
¾tsp
Instant Espresso Powder
2tsp
Vanilla Extract
Add.
3C (675g)
Cold Water
Add gradually while whisking until fully combined.
Cook on medium heat, stirring constantly with silicone spatula, until thick like whipped cream.
Remove from heat and stir in chocolate until fully melted.
6Tbsp (75g)
Unsalted Butter (cold)
Add and stir until melted and icing is glossy.