MAHLBERG, Germany — You could say that Wolfram Siebeck's almost single-handed campaign to transform the way Germans eat began with his discovery that shallots were unavailable in Germany. This was many years ago, in the 1960's. At the time, Mr. Siebeck, who is a sort of German version of Martha Stewart (before Ms. Stewart's legal troubles and without her expansion into a conglomerate), was a culture critic for the weekly Die Zeit and used to attend film festivals in Italy and France. "There I discovered haute cuisine," Mr. Siebeck said, "and I wondered why there is nothing like this in...