But Lawson's newfound American profile and the series' glossy, family-friendly image have now been jeopardised by allegations from her former husband that she is a "habitual criminal" and drug user. The claims threw Lawson's US operation into panic this week.
Executives at Kinetic refused to say whether they would stand by her, and a spokesman for ABC said coolly: "I'm not in a position to comment about or on behalf of Nigella." The second series of The Taste had "already wrapped," and would go out as planned from January 2, she said.
The allegations, a shock to the millions of Nigella's British fans, could wreak even greater damage in America.
Super-model Kate Moss, for example, suffered little long-term effect to her career in Britain after being photographed allegedly snorting cocaine in 2006, but she was permanently tarnished in the US.
"Nigella has no chance in the US if these allegations have credibility," said one TV critic. "This would equate with someone like Martha Stewart or the late Julia Child being exposed as an illicit drug user. Their careers in US media would be over."
"Ordinarily, Americans love a big mea culpa," said a leading Los Angeles celebrity agent. "The problem with Nigella is she's not big enough here for that to wash. For many in America, this will be the first key thing about her that they learn."
Husband's heartbreak
Charles Saatchi has told a London jury of his "heartbreak" at his divorce from Nigella Lawson, claiming that he still adores her and was "utterly bereft" that details of her alleged drug use had been published.
Saatchi gave evidence at the trial of two former aides accused of fraud and spoke in detail for the first time about the infamous London restaurant row that led to the couple's break-up. "I was not gripping, strangling or throttling her. I was holding her head by the neck to make her focus. I wanted her to focus on what we were speaking about," he said, adding they were not arguing about Lawson's alleged cocaine use.
"If you ask me whether I actually knew whether Nigella ever took drugs, the answer is no." Saatchi, 70, an advertising tycoon, and Lawson, 53, a television chef, divorced in July.
But Saatchi told Isleworth Crown Court: "I'm utterly heartbroken that I have lost Nigella and I wish this past year had never happened. If you think this process is giving me pleasure, you're mistaken."
Italian sisters Elisabetta and Francesca Grillo are accused of using credit cards loaned to them by the celebrity couple to spend more than 685,000 ($1.3 million) on themselves.