180g/6¼oz plain flour
220g/8oz light brown sugar
150g/5½oz caster sugar
3 tbsp cocoa powder
¼ tsp salt
pinch of sea salt
150g/5½oz granulated sugar
1 tsp vanilla extract
300g/10½oz dark chocolate, minimum 65-75% cocoa solids
100g/3½oz good-quality white chocolate
10g/¼oz salted butter, softened
150g/5½oz unsalted butter
125ml/4fl oz double cream
4 free-range eggs