She should have told you beforehand, or asked what the menu was when she arrived and then asked to help prepare something she liked.
Given that she doesn't appear to be a very observant Muslim in other regards I think that she's being a complete fool, and is playing manipulative games like the worst women do.
You should have asked, and it was an oversight not to have done, but she knows that you're not a Muslim, and it's an imposition of hers to expect you to cook special food without being asked to. Waiting until you were serving food was an oversight of hers, or else was deliberately picking a fight.
So you go and talk to all your colleagues one by one and explain how nasty she is, and tell whoever's doing it next to make an issue of it. If his notice/e-mail mentions you, it'll show that you're the one who's now thinking ahead, not this silly cow.
