In "Shabbos Kehalacha" (Chelek Aleph Perek Ches), Rabbi Yekusiel Farkash defines *mitztamek veyafa lo* as a food that the **individual** benefits from its continued cooking after reaching *nisbashel kol tzorkoy*, regardless of the benefit to the **dish** itself. He gives the example of meat that gets shriveled up and soft through additional cooking; if the meat will be used only for his family he would be happy to have it softer and it is *mitztamek veyafa lo*, however if he is expecting guests it is *mitztamek verah lo* since he wishes to give them presentable portions and not shriveled meat. He extends this to health concerns; if for medical concerns influence how well done the food should be, that will cause it it to be *mitztamek vetov/verah lo*.

In *ha'orah zayin* he deals with foods that are specifically mentioned in *achronim* to be considered *mitztamek vetov lo*, and discuses when an egg would fall under that category.