50g unsalted butter, softened, plus extra for the tin
2 tsp espresso powder, dissolved in 2 tsp hot water, plus extra for the tin
100g chocolate (70% cocoa solids), broken into squares
45g Bournville bar, broken into squares
50g golden caster sugar, plus 1 tbsp
1 large egg, separated
seeds from ½ a vanilla pod, or 1/2 tsp vanilla extract
4 tbsp plain flour, sifted
4 tbsp golden syrup
coffee or vanilla ice cream, to serve
Heat oven to 180C/160C fan/gas 4. Butter four wells of a muffin tin, and sprinkle some espresso powder into each.
In a pan, gently melt half of each of the chocolates with the butter until smooth. Stir in 50g sugar, then take off the heat and cool for a few mins. Stir in the coffee, egg yolk, vanilla and flour until even.
Beat the egg whites with an electric beaters or a balloon whisk until foamy and thickened. Add 1 tbsp sugar and whisk until it forms shiny soft peaks. Take care not to overwhisk – softer is better if you’re not sure.
Stir about 1/3 of the egg whites into the chocolate batter to loosen, then carefully fold in the rest of the whites using a large metal spoon or a spatula.
Spoon into the prepared tin, then bake for 10-12 mins or until the cakes are just starting to dome in the middle. Cool the cakes in the tin for 15 mins. In a small pan, melt the remaining chocolates and golden syrup together with 3 tbsp hot water, and whisk until silky smooth. Turn out the cakes and serve warm in a puddle of the syrup and topped with ice cream.