Hi Fran,

I'm not sure if Lori will see your question so I'll try to help in the meantime. I haven't made there recipe, but since she uses 2 (8-inch) cake pans as an alternative a 13x9-inch pan should work. If it looks like too much batter when you get it in the pan (about 2/3 full) bake the extra batter as muffins.

Happy Baking!

Betsy