I’m taking a lot of inspiration (that means “I’m trying a lot of recipes”…) from a book bought in the USA last summer: Baking - A common sense guide, Bay Books. It’s funny because it shows pictures of how the cake should looks like, how it looks like if over or under baked. So you don’t see only perfect and beautiful treats, but also ugly, pale or burnt things.
Nonetheless, in this case I preferred not to try the over or under baked version!!