my son wants a rice krispie wedding cake like we saw on theknot. The three layers look to be at least 6" deep. How can we mold square rice krispie cakes that are that deep? Most cake pans are 2"-3".

Can you mold oneside.....and then the other and press them together?

Rice krispies fall apart when they are hot, but when they are warm you can shape them however you like. Use wax paper to keep them from sticking to your hands. I did this while shaping an iron man head and it worked perfectly.