Cake Disaster

Apparently me and cakes are not meant to be. Went to my cake class last night, learned nothing other than we provide our own cakes. Fine, whatever ... not what I thought when I signed on for this, but I'll deal. Got 1 mix to make my cake for class. Decided tonight I wanted to try to bake, torte, frost, and decorate a cake for work tomorrow ... mixed up my mix, put it in my 2 8" round pans, baked (25 degrees lower than called, per instructors recommendation as I'm remembering) ... looked nice and golden when I pulled them out of the oven. Cooled, flipped out of pan ... and then they cracked as they cooled. I'm so annoyed (cake's really good, though). Gotta figure out what I did wrong, so I can try again ... since I have to have cake for class. Took pictures of the disaster after the crumbling (and some sampling :) ) happened.