I don't know if it's my oven or cake mixes have changed in recent years, but anytime I bake a cake from a cake mix, particularly Betty Crocker, it deflates to half its height and has that dark line at the bottom of the cake. Any suggestions?
Thanks,
Butter

well, when i make the Betty Crocker cakes, i usually place them in a long rectanuglar tin. the brownies dont deflate and the cake havent done such a thing for me. Let it cool down before you do anything to it.

Ill make sure what i do next time so i can tell you for sure

My first question would be, do you flour your pan? If you do, try skipping that step. It sucks the moisture out of the cake and can cause it to fall. Another thing is basically, make sure it's totally done before you remove it. Sometimes that unbaked center will fall.

I think i've read that it has to do with slamming the oven door when it's halfway through cooking? Maybe that's an old wives tale though...

Our oven is old so sometimes it leaves a little gap. That's probably why i never cook frozen fruit pies properly.