Several years ago, when I was managing a state park resort, I maintained a standing complaint against a particular head chef who insisted on serving INSTANT MASHED POTATOES to the guests in my beautiful main dining room. I bugged him about it daily and he would always say that he "doctored them up" and no one could tell the difference... but I COULD tell the difference. Long story short, my birthday rolled around and all the waitresses and kitchen staff surprised me that afternoon with a beautiful birthday cake when I showed up for lunch. The aggrieved chef joyfully served me the first piece and I took a big bite ONLY TO DISCOVER THAT IT WAS PURE INSTANT MASHED POTATOES MADE ONLY WITH WATER AND FOOD COLORING!!! YUK!!! So, the moral is, "Never cross the chef." You put this thing together pretty much like a regular birthday cake, piping on the colored "icing" (food colored mixed potatoes. You can even make the inside yellow (more food coloring) if you wish. And please..... rate me on the "effectiveness of the (unpleasant) surprise" -- not the flavor, folks. And, yes, there are people who really do deserve a cake like this, such as myself! Oh, yes, I almost forgot.... there are about 20 servings but I assure you that only one of those servings will get tasted.