This cake from Catalina's Cactus Cuisine (Catalina Junior Woman's Club of Tucson, Arizona, 1968) is really just a Wacky Cake by another name.
I'm not sure naming a chocolate cake after a super-sized outhouse is a great idea. Well, unless you want the entire chocolate cake to yourself, in which case, well played, Joan. Well played.
P.S.- You can be thankful I didn't go with the Urban Dictionary version of three-holer. (I'm sure that's not what Joan meant anyway.)