Shabbos morning we usually don’t eat cholent but rather some sort of meat dish and sides. When we go out to eat Friday night we don’t want to leave the platta on the whole night since it makes the house very hot and uses more chashmal…
Putting the food on the platta to heat up isn’t a problem because we can put it on top of another pot, etc (there is no liquid as well in the dishes, etc.) B’kitzur b’ofen heter…
But can we have the platta on shabbos timer and have it go on at 9 am shabbos morning and then put the food on (in a permitted way) after the platta is hot?
Since your putting the food on the palata is permitted on Shabbos, because it is fully cooked, dry, and placed on the palata in a way that it will not be considered nesina l’chatchila, the fact that the palata was not on the whole Shabbos will not change anything, and it is permitted. What is brought in the poskim regarding using a Shabbos clock to cook foods or when the food was is directly on the palata, is not applicable here, as there is no issue of bishul shehiya or chazara.