A few months ago, I became the proud, and slightly sheepish, owner of what must be the world's most expensive food processor. The Thermomix costs about $1,500. It not only chops the food but weighs the ingredients and cooks them for you while stirring constantly. Perfect hollandaise and flawless béchamel can be produced in minutes with virtually no effort.

After seeing one last summer in the home of a friend, I promised myself one if I completed a particularly large and time-consuming...