Star of David Cookies in the 17th Century

Rabbi Yair Chayim Bacharach (1639-1702) was a German rabbi, initially in Koblenz and remainder of his life in Worms and Metz… He was the author of Havvot Yair ("Villages of Yair") a collection of responsa where he answered a question about breaking cookies on Saturday, on which there were drawings of Magen David or other images. Right after this question he tells about a habit to write bible verses on cookies and let babies eat them. It is not clear to me if the Magen David cookies were meant for babies but it seems that this emblem was well known among the Jews in Germany in the 17th Century who used to draw it on bakery products like cookies and Matzos.