Yesterday the German writer and translator Mirjam Pressler was awarded the Buber-Rosenzweig medal, which honours individuals or institutions that contribute to Christian-Jewish understanding. She has written a million trillion books for children and young people, none of which I have read apart from Die schönsten Erstlesegeschichten, which was kind of dull but that's a pretty common phenomenon in the world of first readers. A lot of her writing focuses on outsiders and particularly on Jewish children. A couple of her novels have made it into English too but seem to be out of print apart from Halinka (trans. Elizabeth D. Crawford). What you can still get hold of easily, however, is Treasures from the Attic, a non-fiction book about Anne Frank and her family.
Pressler is quite an expert on Anne Frank. She learned Dutch so as to translate into German, and did in fact edit and re-translate the "definitive edition" of the diary. She also translates from Hebrew, including Zeruya Shalev. She's won all the prizes going for young adults' writing and I'd say she's one of the most highly respected children's writers Germany has. You can read a neat little English interview with her on the Deutsche Welle website.