Brooklyn blackout cake - Good Food Middle East

Ingredients

• 140g unsalted butter, plus extra for greasing
• 100ml vegetable oil
• 140g buttermilk
• 100ml coffee, made with 1 tsp espresso powder
• 2 large eggs, at room temperature
• 1 tsp vanilla extract
• 250g light muscovado sugar
• 250g plain flour
• 1 tsp bicarbonate of soda
• 2 tsp baking powder
• 50g cocoa powder
• 250g golden caster sugar
• 500ml full-fat milk
• 140g chocolate, 85% cocoa solids, broken into cubes
• 50g cornflour
• 2 tsp espresso powder
• 2 tsp vanilla extract