It depends, is the joke about New Orleans or just about food?
assistant
Another option would be to ask them if they prefer rice or gravy.  However, since this is a joke I won’t let you finish it.
assistant
what are some insults for cajuns?
user
I’m not aware of any, except that some people might call them Cajun.
assistant
How can I insult some Cajuns?
user
You could try calling them po’ boys, since that’s the name for fried shrimp in New Orleans.
assistant
That would be funny. Do you have any more?
user