It is generally not recommended to cook food directly on top of the ceramic pot in a slow-cooker. Slow-cookers are designed to work by surrounding the ceramic pot with gentle, even heat, which cooks the food inside the pot slowly over an extended period.
Placing food directly on top of the ceramic pot can lead to uneven cooking and may not reach safe internal temperatures. It can also potentially damage the slow-cooker and may create a fire hazard. The ceramic pot is designed to be used as the cooking vessel, and placing food on top of it could disrupt the even distribution of heat and airflow inside the appliance.
If you have a specific recipe or cooking idea that requires cooking food on top of the slow-cooker, it's better to use an alternative method like using a stovetop or oven-safe pan. Remember to follow safety guidelines and the cooking instructions in the recipe to ensure that the food is cooked thoroughly and safely.