Every time she says something like that, I'd be tempted to say:
"I'm sorry can you say that again, I'm not sure I heard you right" or
"I don't understand, can you explain what you mean"
and if she says "Ha, never mind it was just a joke, where's your sense of humour", I'd be replying
"Oh, but I didn't get it, can you say it again for me".
Forcing people like that to explain themselves, particularly in front of others isn't something they usually enjoy doing and may make her think twice about doing it again.
Or, you could just own it and say:
"Maybe, but I like it - do you want to try some" or
"You've mentioned I'm short/ginger so many times now, I think you must be a bit jealous" etc.
I'd also be wondering what kind of friend she was - but that is a whole other thread!