Why do cakes hot out of the oven have a rancid smell?

Cakes that come hot out of the oven may sometimes emit a rancid smell due to the breakdown of fats used in the recipe, particularly if they are old or have not been stored properly. Additionally, if the cake contains ingredients like butter or oils that have gone rancid, they can produce off-putting odors when heated. Overbaking can also lead to a burnt smell, which might be mistaken for rancidity. Ensuring fresh ingredients and careful baking can help prevent these odors.