Can I mix 3 cake boxes at the same time? I own a pro. 6qt kitchen aid mixer, so 3 or 4 boxes seem to fit but I only mix 2 at a time. Thanks....

If your mixer can hold it I don't see why not, you're already mixing 2, right? Maybe just go a little slower in the beginning to make sure it's all incororated so there is no "cake mix cloud" coming out of the mixer when you turn it on high.

In my 60 qt I would mix as many as 10-12 at a time so yes, if you mixer is big enough, go for it

I say go for it.

Thank you all for responding. I was afraid to do it that way thinking the cake would not cook even. I will try it that way on my next cake .
Blessings