Ok Guys I have to make a 11 x 15 x 2 in. Sheet Cake....

This is my first sheet cake and I do not know how to correctly make the right amount of batter, The paper that came with the pan says approx 11 cups. I have only done round an cartoon pans. EKKKKKKKKKK

Can I put to boxed mixes together????

Please help I have to have it for 1st thing Sat. Morning

Yes, you can definitely mix 2 mixes together at the same time.

When I make this size of pan, I use 2 1/2 box mixes. I actually mix up 3 cake mixes. I pour it into the pan until there is roughly 2 1/2 mixes in the pan. Then I use the leftover batter to make a smaller cake for my family. (I can only mix 2 cake mixes at a time in my Kitchen Aid)

Another tip would be to use an inverted flower nail (or 2) when making this size cake. It will conduct the heat into the middle of the pan and your cake will bake more evenly, and not be undercooked in the middle and overcooked on the edges.

Hope this all makes sense. Please let me know if I need to clarify something!

Yes, you can put Boxed Mixes together. I box is usually 4-5 cups, unless you doctor it. I usually mix 2 at the same time when I'm baking a larger cake, the I use any leftover batter in a smaller pan & freeze it for a later date.