They have light meals/filling snacks such as Lamacun (flatbread with a small amount of meat on it), Turkish Pizza, and salads. They have a selection of breakfasts (standard German, I think) ranging from small to large.
The best thing we found there is an amazing assortment of really wonderful Baklava, which you can eat as dessert or take home a big box, at a very (very) reasonable price – 10 to 13 Euro per kilo.
They speak German but do have English-speaking staff, and all were friendly. The owners run a travel agency next door.