They are called flapjacks! They come in two flavours peanut and coconut, although I found it difficult to tell the two apart as they taste very alike.
They taste very dry and are an acquired taste.
My first experience of flapjack had me turning green and gagging:9529: Mainly because you just taste the vitamins etc....best to leave them until you are a couple of weeks on LT and your body has adjusted to the all the vitamins, minerals and trace elements.
Being desperate for something to chew I gradually grew to like them and found them very filling and handy for when out and about.