[Annabelle]

This is not a cure for the biscuit habit BUT you can buy biscuits that come in individual sachets  within the box. Belvita do such a thing, they are called breakfast biscuits and come in various flavours. This means that once the box is open you are not left with a whole packet of biscuits, which you either end up eating the whole lot or they go soft. It is not easy. So, the portions are already decided for you.