Shalom Rabbi,

Thank you for your answer. Let me rephrase my questions:

– If I have a fully cooked dish, can I warm/reheat it with an electric oven? We have at home one of those small electric ovens used to reheat pizza, toast bread, etc. And it has the option to set the temperature and to just warm the food (I can set that before Shabbat). Can I turn it on manually on Shabbat to warm fully cooked food?

– The same principle can apply to a plata? Can I just turn on the plata manually on Shabbat in order to warm fully cooked solid food?

My understanding is that I am not creating fire nor heat directly since it takes time to actually reach a temperature able to warm the food in both cases. It seem that it is gramma.