The cause was cardiac arrest, said a friend, Nicole Mabry.
Ms. Powell was a bored administrative assistant, living in a cramped New York apartment on the cusp of turning 30, when she launched her project in 2002 in “one of those panicked, backed-into-a-corner kind of moments,” as she later told the New York Times. Her blog, the Julie/Julia Project, was a humorous, idiosyncratic catalogue of her attempt to cook all 524 recipes from her mother’s dog-eared copy of “Mastering the Art of French Cooking,” Child’s 1961 classic, which required her to scour grocery stores and butcher shops for rare ingredients (kidneys, sweetbreads) and learn to peel potatoes into an olive shape.
The blog brought her a wide audience and eventually a publishing deal.
Her book, “Julie & Julia: 365 Days, 524 Recipes, 1 Tiny Apartment Kitchen” (2005), sold some 1 million copies and was adapted into a 2009 movie. Written and directed by Nora Ephron, “Julie & Julia” starred Amy Adams as Ms. Powell, whose story was intertwined with that of Child (played by Meryl Streep) and Child’s husband, Paul (Stanley Tucci).
A complete obituary will be published soon.