Was it the scallops that cost Walter Scheib his job, or the last state dinner he made for the Bushes at the White House, in honour of Kenya's President Mwai Kibaki?
The menu that evening in October 2003 consisted of a salad of avocado and tomato in toasted cumin dressing, followed by grilled halibut, scallop risotto with lobster sauce, and roasted rack of lamb. The dinner appears to have been a notable success. But within 15 months the chief usher, Gary Walters, the man in charge behind the green baize door at the White House, gave Mr Scheib his marching orders as executive chef.
Mr Scheib was appointed to the post by Hillary Clinton and had occupied it for 11 years. Outwardly the parting was low key and polite, as is customary at such rarefied levels. All the chef would say was that he had evidently failed to meet the "stylistic requirements" of Mr Bush. Earlier this year, however, such courtesies were blown aside by a piece in the Wall Street Journal. According to an unnamed official from the East Wing - the formal and residential part of the White House mansion - the chef had been dismissed because he had displayed "arrogance" in continuing to prepare scallops for the First Family, even though he had been told that the President couldn't bear them.
Nonsense, Mr Scheib retorted in a rare public utterance pertaining to his previous employers: "There was never any request to take scallops off the menu." Had there been such a demand, he said, "there would never have been a scallop in the building". Another anonymous complaint, relayed to the press, was that he invariably served his vegetables "julienned and presented as a pyramid" - an elaboration unlikely to be appreciated by a couple of homebodies from Texas. And there the mystery has rested, until now. But in a couple of months the chef is publishing his memoir of life in the White House, of food and foibles under two First Families.
Do not get your hopes up. After State of Denial, Bob Woodward's pitiless snapshot of life in the dysfunctional administration, and Tom Rick's Fiasco, a devastating account of the mismanagement of the Iraq war, The White House Chef will not be the book that finally destroys the Bush administration. But it contains some entertaining titbits nonetheless and, with its dedication to Mrs Clinton, leaves no doubt which of his two employers Mr Scheib found more professionally congenial.
We learn, for instance, that the Texan transplanted to Washington is not too fond of either "wet fish" (steamed, poached or boiled) or of green food - a genetic trait, doubtless, given his father's celebrated aversion to broccoli. Mr Scheib also throws some light on that still mysterious 2002 episode when Mr Bush choked on a pretzel while watching a football game in his private quarters. The offending object, the chef reveals, was an "Amish-made organic flour pretzel". How that exotic specimen reached the presidential snack tray is not clear.
Other dislocations to routine in the White House kitchen were Chelsea Clinton's sudden conversion to vegetarianism, and a demand by Jenna and Barbara Bush for specific calorie counts for meals. However, you suspect that the chef just got a bit bored.
With George's known preference for being in bed by 9.30pm, the White House hasn't exactly been the glittering social hub it was in the days of the Kennedys, Reagans and Clintons. This Bush has given barely half a dozen state dinners in six years, compared with the 20 offered by his father in a single four-year term, 28 by the Clintons and 50 by the Reagans.
Hillary Clinton, writes Mr Scheib (pictured), wanted to showcase the best of American cooking. The Bushes, however, prefer simpler fare. The President loves a sandwich of peanut butter and jelly, or grilled with Kraft cheese - not exactly challenging for the thoroughbreds in the White House kitchen.
Most intriguing, however, are the hints of turmoil in the East Wing. Cathy Fenton, Laura Bush's first social secretary, talked when she left of the "volatile" environment. Now Mr Scheib takes aim at Lea Berman, Ms Fenton's successor. Enough of this "country club food", Ms Berman told him after her arrival in 2004. "Yuk," she wrote on one suggested menu, and complained that his vegetables were "always overcooked". A month later Mr Scheib was out. Maybe it wasn't the scallops after all.