Hi all! Ds's 5th bday is coming up here and I am making him a cake. I got an 11x15 inch sheet cake pan made by wilton but I have no idea how much cake mix it will take to make it??? Any ideas? I am planning on using the wacky cake recipe which I have used with good results on the wilton shaped pans before but this pan just seems like it will need a lot more batter to fill it up. Any ideas or suggestions would be appreciated-thanks!