Ali, at weaning age (now 6 months plus), a small ice cube would be one portion. The aim of weaning at this age isn't to fill them up with food, it's just to introduce a new texture. The general rule is that a portion is the size of the palm of their hand, a 6 month old's palm is roughly the size of an ice cube. Carbs are a little bit more, roughly the size of their fist. the same applies with adults. It's really confusing IMO, there is guidance online but it's a portion of grapes is 10 grapes (ish), a portion of mango is 4g etc so it's not easy to follow.