What to buy a German teenager for Christmas to make them feel at home?

I'm staying with my girlfriends family over Christmas and they have a German exchange student staying with them also (we're English).

To my knowledge she's never spent a Christmas away from her family before and I imagine she might feel a little homesick. She's (I think) 15 or 16 and I wanted to buy her a small present - maybe something that is traditional for German Christmas celebrations that isn't really part of English tradition that she might miss. I didn't want to go crazy (I've never even met her before so it would be a bit weird to buy her something too expensive!)

Any ideas?

Edit: thank you all for your tips! In the end I decided to just get a fancy diffuser thing for her bedroom from a British brand that I'm not sure is in Germany and the stuff to make Vanillekipferl (pronounced van-ill-kip-ferl ?) because they sound easy.

It's a nice idea to buy German food but the best I could do would be to get some rubbish, mass produced version that wouldn't be as good as her grandmother makes anyway and, as some have said, might just make her feel more homesick anyway.