One of the first steps in our recipe cards is always an instruction to preheat your oven. This is essential because of how ovens work in getting up to the right temperature! When an oven gets turned on, the bottom (or in some cases, top and bottom), heating elements in the oven are switched on and starts to heat the oven. It is only after a period of heating that the oven comes to the desired temperature, and the oven's heating elements will turn off and on automatically in order to maintain the desired temperature. Without preheating, it's likely that your bakes will take longer to be done and may not even bake properly!