In Hilchot Shabbat, there is an issue of "Hagasah"-stirring a fully cooked pot of food. The Shulhan Aruch rules that it is prohibited to stir the food, if the pot is still on the fire. Even though it is fully cooked, and the stirring will not enhance the cooking process, it is "Mehezeh K’mevashel"-it looks like cooking; also, one may come to stoke the coals. Therefore, it is prohibited to stir Hamin in a crockpot, even though it is fully cooked, and they just want to mix the spices.
Many people are accustomed to sampling the Hamin on Friday night. Is this permissible? Does removing Hamin from the pot with the ladle constitute stirring? The Halacha permits doing so. Even actively stirring a fully cooked food is only prohibited M’drabanan (rabbinically), because of a Gezerah, the Halacha does not institute an additional Gezerah that partaking with a ladle will lead to stirring.
Hacham Ovadia writes an even bigger Hidush. He rules that it is even permissible to stir a pot of fully cooked food on a Blech or hotplate (as opposed to a crockpot). Since those are not the normal way to cook, there is no concern of "Mehezeh K’mevashel" and no issue of stoking the fire.
SUMMARY
It is prohibited to stir a fully cooked food in a crockpot, but it is permissible to dish out from it. However, it is permitted to stir a fully cooked food on a Blech or hotplate, and certainly to dish out from it.
