Brooklyn blackout cake
SERVES 12 PREP 30 mins plus cooling and at least 5 hrs chilling COOK 40 mins MORE EFFORT V
140g unsalted butter, plus extra for the tins
100ml vegetable oil
140g buttermilk
100ml coffee, made with 1 tsp espresso powder
2 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
For the custard
250g golden caster sugar
500ml whole milk
140g chocolate (at least 85% cocoa solids), broken into pieces
50g cornflour
2 tsp espresso powder
2 tsp vanilla extract
First, make the custard. Put all the ingredients, except the vanilla, in a large pan and slowly bring to the boil over a low-medium heat, whisking continuously until the chocolate has melted and you have a