I check the internet daily for "keeping food hot"; and the most practical way to keep food hot at the table -on the plate- is using hotSmart plates, they are ceramic plates capable of remaining hot for 30 minutes + (your hand will hardly withstand the heat), so that is hot, not warm. The plates are designed to keep food hot and it is the first functional change to the ceramic plate in centuries. By the way, they need only one minute preheating in the microwave oven and can even be handled safely by the rim with the bare hands. The rim does not get hot.
Will you please Google "keeping food hot at the table" and let me know if there is anything better? I need to stay ahead of my competitors.