I'm pretty sure that when I was younger we didn't eat meat on good friday but fish was allowed and I was raised a catholic (unfortunately). Is your girlfriend catholic?
She is a Catholic and as such must not eat meat on Fridays during Lent, and many Catholics adhere to this all year round - no meat on Fridays.
Proper lasagne is not the nasty stuff in supermarket freezers or on the pub menu - it is a very rich meal indeed and considered a traditional treat in Italy suitable for high days and feast days.