A combination oven includes radiant cooking lamps and a magnetron for delivering cooking energy to a cooking cavity. The oven is operable in a speed cooking mode utilizing both radiant and microwave energy, a microwave only cooking mode utilizing only microwave energy, and a radiant only cooking mode utilizing only radiant energy. A radiant cooking element is briefly energized upon user command during microwave only cooking modes and lower power radiant cooking modes to illuminate the cooking cavity for visualization of cooking in progress. A duration of cavity illumination is limited to prevent cooking of food during cavity illumination.