Lettering, numbers, pictures that are part of a cookie or cake itself. (It's all one dough).
הכנה לחול (Preparations for a Weekday): Is There a Limit to the Amount of Exertion Used When Doing the Action?;
Various Examples of Where We Have the Problem of דבר דבר (Dabair Davar) and ממצוא חפציך (Mimtzo Cheftzecha);