1 tsp bicarbonate of soda
175驳/6录辞锄 soft brown sugar
175驳/6录辞锄 caster sugar
350驳/12录辞锄 plain flour
1 tsp salt
1 tsp vanilla extract
350驳/12录辞锄 dark chocolate, crumbled
225g/8oz butter
2 free-range eggs