Why doesn't my electric oven cook food evenly?

When food is cooked unevenly in an electric oven, it is usually cooked more at the back than it at the front. This is due the position of the fan. The fan is usually positioned at the back of the oven. The fan is designed to circulate the hot hair, but a lot of it is just pushed forward. Therefore the hot air is hitting the side of the food closest to the fan and cooking it more than the rest of the food. This is obvious when you are cooking pizza, as you can tell from the crust where it has cooked. To prevent this, rotate your food 90 degrees every quarter of the cooking time.