I will be making a 11x15 2 layer cake to carve into the Perdue "P" for a grooms cake. How many cake recipes/cups of batter do you think I need? I plan to make 2 cakes, level, fill, carve frost & fondant them. Don't want to try and torte that large of a cake. What are your ideas??

http://www.wilton.com/cakes/making-cakes/baking-wedding-cake-2-inch-pans.cfm

An 11x15x2 pan requires 11 cups of batter for each layer:

http://www.wilton.com/cakes/making-cakes/baking-party-cake-2-inch-pans.cfm

It's not necessary to torte the layers, one layer of filling between the layers should work fine.

HTH

If you are using box mixes, it takes two of them....

Thank you all. I thought 10 cups would do it but I'll go for 11 to be safe. Now just have to figure out how many cups my recipe makes. Not a mix. Is there any formula for that?

I do it the old fashioned way, I make a batch of my batter and then measure it out cup for cup and make sure to write down how much it makes. Then in the future you'll have a MUCH easier time figuring out how many "recipes" of your batter you need to make.