Dispatched for a general fire alarm; the occupant is on site without the proper passcode; the occupant states there is no fire. Engine 12-5 responded non-emergent to confirm the false alarm, all other personnel on standby at the station. Upon arrival, the occupant states that there had been a fire in a built in oven resulting in the alarm activation and that the fire was out prior to fire department arrival. Investigation revealed no damage from the reported fire prior to fire department arrival. The use of the built in oven had been discontinued. We investigated the area near the oven visually and with the thermal imaging camera with no extension of the original fire noted. Melted plastic is noted in the bottom of the oven. This information is provided to the homeowner. Engine 12-5 crew cleared the scene and returned to quarters.