I am using box mix. How many boxes does it take for a 12in. round and how long to cook? I am doing 2...

I made one a month ago and I used two boxes plus a box of pudding mix. Baked perfectly right to the top and didn't overflow. I think they took over an hour at 325 and I never used flower spikes or a heating core either

You need to get familiar with this chart: http://www.wilton.com/cakes/making-cakes/baking-wedding-cake-2-inch-pans.cfm

the above link is what i use as well for all of my cakes and it works out well! the cook times are a little off but the amounts are always right on! but it looks as though it will be 7 1/2 cups of batter per 12" pan.

2 and 1/2 boxes

For each 12"x2" pan I use 1 1/2 mixes OR one batch of my *original* WASC recipe.

I use two boxes (8 cups) at 350 for about 50 minutes, providing I have nothing else in the oven at the same time..
It's become a popular size for me...

So....how do you measure out the "1/2" part? What I'm getting at is.....if I make a 2-layer (each 2 inches) 12 inch round....I'm going to need 4 1/2 boxes. Is that right? So..how do you compensate with the other ingredients when it comes to the "1/2" part?? If it calls for let's say 3 eggs per box....what do you do about the "1/2?" lol! Help!!

Don't half the mix. Mix it up as directed, measure amount needed for your cake and use the rest for cuppies.

If I am doing 2---12"x2" rounds I make 3 boxes of CM, and just eyeball the batter between the 2 pans. HTH MMEX