Lettering, numbers, pictures that are part of a cookie or cake itself. (It's all one dough).
Mentioning an Action on Shabbos That Could Be Done the Right Way;
Pickling Foods, Salting Foods: Is One Allowed to Put Back a Pickle into Its Jar Which Was Taken Out?;
What Are Some Examples of Drinks That Are Not Allowed to Be Strained Out מדרבנן (M'drabanan)?;