If a cake has ripples on its top after baking, what might be the most likely cause?

When a cake has ripples on its top after baking, one of the most likely causes is the use of a convection oven. In a convection oven, a fan circulates hot air around the cake, which can lead to uneven baking if the temperature is set too high or if the cake is too close to the fan. This movement of air causes the surface of the cake to set quickly, while the inside continues to rise, potentially leading to a ripple effect on the top.

Using a convection oven requires adjustments in baking time and temperature, and if these adjustments are not properly made, it can result in cakes that do not rise uniformly or set evenly, leading to a surface texture that appears rippled. Understanding the dynamics of heat circulation in convection ovens can help avoid common baking issues, such as the one described in the question.