225g/8oz plain flour
½ tsp baking powder
250g/9oz soft light brown sugar or light muscovado sugar
75g/2¾oz golden or white caster sugar
½ tsp sea salt flakes
1 tbsp vanilla extract
125²µ/4½´Ç³ú white chocolate, chopped into rough chunks
175g/6oz unsalted butter, plus extra for greasing
2 free-range eggs