What does Gefeli mean?

"Gefeli with your propedeuse!" was written in big letters on the homemade cake.

Dutch student slang. This is a Dutch word. You will hear it a lot at Dutch universities, student associations and in student houses.

You mostly see it in texts and on birthday cards, where the full word feels a bit too formal. Dutch people congratulate everyone at a birthday, including the family of the birthday person. So you will need this one a lot.