If it was her article published under her byline by the NYT, then fine, I’d expect US spelling to be used. But if the NYT is quoting her writing from somewhere else, then they should have kept the original spelling. Prime rule of copy editing: you don’t edit quotes.

Did she really write ‘omelet’? That’s the American spelling, and I very much doubt she would have used that. The French spelling, omelette, is what is used in the UK.