My co-worker attempted to make three cakes from scratch and each cake sunk in the middle a few mintues after taking them out of the oven. Does anyone know why this happens?

Could be a few things.
1) Over mixed the bater
2) Baking soda or powder was old
3) Cake was not completely done

Also - she might have deflated it by slamming the oven door or jostling the oven rack. I accidentally picked up and dropped an oven rack with a cake on it and stood there in dismay as it sank like a rock in the middle.

Most often the cake is underbaked.

I have this problem a lot lately...............I use the Super Enhanced Recipe from this site. I use the bake even strips and reduced the baking temp to 325 degrees and bake longer. Test for doneness before taking out of the oven and it still falls in the middle when the cake tester is coming out clean.

Any suggestions?