In the published piece, M.I.A. is described as "eating a truffle-flavored French fry" as she mused about what type of artist she is. According to the tape, it was Ms. Hirschberg who introduced the concept of fry-ordering.
"They have, like, truffle, they have like three different kinds, it's very elaborate," Ms. Hirschberg says on the tape, explaining the menu to M.I.A. at the Beverly Hills Wilshire Hotel. M.I.A. said that, yes, she would like a starter. "Can we order the French fries that come on the bar menu, the basket?" Ms. Hirschberg instructs the waiter.
This only came out because MIA was more canny than Hirschberg expected - she secretly taped the interview, probably because she knew Hirschberg has a reputation for doing seemingly innocuous interviews that turn into scathing character-assassinations.
Hirschberg is either lying or being disingenuous when she says that "I don't think the French fries illustrate that much about her character", because it's clearly meant to illustrate something. I would call it Dickensian in its upper-class-is-morally-defunct symbolism, except that I think Hirschberg's unsubtlety would make even Dickens blush. (Hilariously, Hirschberg criticized MIA's immediate response to her profile - MIA posted Hirschberg's phone number on Twitter - as "unethical".)
As a brief aside: The Observer also notes that we might be at a point where journalism needs to tighten its standards, since every interviewee now has the potential to publicly call them on their bullshit. And that might be the most interesting development to follow.