Yes, I remember. I think I read it for the first time in high school. Surely someone made toast, though ... perhaps some children.
I can’t remember anything about toast in that story. On the moon, standard breakfast items would have been luxuries, and expensive.
I think they talked about plankton, or algae.
By the way, if we ever have to evacuate the Flying Castle under emergency conditions, the food supply and variety is going to be ... limited.