as an extra amount of sth in addition to what has already been done or given :
Use 50g of rice per person and an extra spoonful for good measure.
as an extra amount of sth in addition to what has already been done or given :
Use 50g of rice per person and an extra spoonful for good measure.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005