A huge thank you to Conchita, Canadian45 and Amy! :lol:
In fact, I was very surprised to read in Collins Cobuild English Guide that we take cake, banana or egg for dinner etc. When a person says I had cake for dinner he is only concentrating on the product(meal) he took and not on the number. ‘I will take cake for dinner tonight.’ may include any number of cakes, maybe only two spoons. So the more natural way to say (according to the book)
I had egg for dinner–and now this may include different kinds of egg the person had–he ate until he was full.
I really do not know. I would like to know from you people. Is it again only bookish?? :shock: