Date and toffee pudding with caramelised bananas and the ultimate toffee sauce

Cooking ingredients

2 tsp bicarbonate of soda

125g/4½oz soft dark brown sugar

250g/9oz chopped dates

demerara sugar, for dusting

175g/6oz demerara sugar

150g/5½oz plain flour, plus extra for dusting

pinch salt

1 tbsp black treacle

1 vanilla pod, split in half and the seeds scraped out