What is the most expensive tool in your kitchen that you have only used once (or maybe never!). I live in an apartment, so I don't have unlimited space. I don't own a full-sized food processor or a microwave oven. I do own a Kitchen-aid stand mixer and more knives than I need including the "X50" cleaver used by Mario Batali on Iron Chef. (It is really a SG175 Sanelli 112628 Premana Professional 11 Inch Heavy Knife--"Now, that's a knife" as Crocodile Dundee once said.) But while expensive, I have used these items more than once. But I have only used my Matfer Mandoline 2000 Pro once, which makes it dollar per use the most expensive tool in my kitchen. Now what is your (relatively speaking) white elephant?