Lettering, numbers, pictures that are part of a cookie or cake itself. (It's all one dough).
חסרון כיס Machmas Chesron Kis: Setting Something Aside Because It's Very Precious;
Is One Allowed to Relieve Pressure from a Blister, Pimple, Boil, etc. on Shabbos?;
Is there a problem with food NOT stuck on to lettering. Washing off dirt on one's hands.