The present invention provides a microwave oven and a method of operating a microwave oven, which minimises user involvement when heating a food item to a desired target temperature. According to the invention, the initial temperature of the food item is measured prior to the heating process, and the required heating time is determined automatically based on the initial temperature, the target temperature, and the amount of food as entered by the user. In order to heat a food item to a desired target temperature, the user only needs to position a container for temperature measurement and enter the amount of food. In particular, the present invention is preferably adapted for heating of baby food, such as baby milk contained in a baby bottle, and in such case the target temperature is preferably preset to about 37.degree. C.