Un dessert sans fromage est une belle a qui il manque un œil.

A dessert without cheese is a beautiful woman missing an eye.

Un repas sans fromage est une belle qui n’a qu’un œil.

A meal without cheese is a beautiful woman who has only one eye.

The meaning of both sentence is a metaphor to express that a meal where you go straight from the main course to the dessert without first serving cheese would be the equivalent of a beautiful lady missing an eye: almost perfect yet conspicuously missing something fundamental.