I thought it would probably be to do with mozzarella
Dd got her letter yesterday, by the way - she was delighted. She's almost finished writing hers and we'll try and post it tomorrow - no point doing it today with the postal strike. Dd is a bit self-conscious about her handwriting (they don't do joined-up writing yet, and she was terribly impressed that your dd does!) but is doing her best. I'm hoping that your dd won't need a translation ...