In this paper, a model-based temperature control method for cooking appliances is proposed. Due to structural and sanitary limitations, no sensor for the temperature of the cooking object is equipped in general. After constructing a state space model for the heating process and identifying the model parameters for each distinct volume of the cooking object, a state observer is designed. By using this observer as a softsensor, feedback temperature control is implemented instead of the conventional model-less on-off pattern control. Its high tracking performance is demonstrated via numerical examples and experiments.