Just tell them it's pumpkin, and they'll love it:
Holiday Left-Over Sweet Potato Cake
I served it warm and with a generous sprinkling of confectioner's sugar.
And it contains beer. I accidentally put in 1 cup instead of 1/2 cup...just took a bit longer to bake. Happily, we have beer on tap around here. My husband loves it when I use the kegerator.