Delicious!

In the novel's opening chapter, set eleven years before the main action, ten-year-old Billie Breslin helps her Aunt Melba and older sister Genie perfect a gingerbread cake for their father's birthday in the Montecito hills. Billie surprises everyone by suggesting fresh ginger, orange peel, and cardamom, demonstrating an extraordinary ability to imagine and combine flavors in her mind. After multiple attempts, they produce a perfect cake. Aunt Melba tells Billie she inherited this gift from her late mother, marking the first time anyone has compared Billie favorably to their mother, since the brilliant, beautiful Genie is always the one people say she resembles.

Eleven years later, twenty-one-year-old Billie has dropped out of college to interview with Jake Newberry, editor of Delicious! magazine, at the grand Timbers Mansion in Greenwich Village. Jake requires every candidate to cook for him, and Billie, who now has panic attacks in kitchens, nearly faints. The hostility of Maggie, the executive food editor, paradoxically jolts her back to focus. She bakes her gingerbread, even Maggie declares it fantastic, and Jake hires her. Billie moves to a tiny walk-up on the Lower East Side.

Billie quickly discovers the magazine's eccentric culture. She meets Richard Phillips, the creative director, and learns about the absent travel editor, Sammy Stone. Maggie sends Billie on an errand to Thursday Brown, a famous chef, who detours her to Fontanari's, a century-old Italian food shop in Little Italy. The owner, Sal Fontanari, takes Billie on a tour of New York's food artisans, marveling at her ability to identify ingredients by taste. The outing turns out to be the "Sal Test," a ritual Jake uses to screen assistants for genuine curiosity.

As Billie settles in, she handles the Delicious! Guarantee, the magazine's longstanding refund promise, fielding calls from readers like Mrs. Cloverly, a querulous repeat caller from Cleveland. She works weekends at Fontanari's, where Sal's wife Rosalie welcomes her and a regular customer the staff call "Mr. Complainer" provides weekly entertainment. Diana, a test-kitchen cook, becomes Billie's first real friend. Throughout the novel, Billie writes emails to Genie's inactive inbox, processing grief and maintaining a connection with her dead sister. Sammy, the flamboyant sixty-two-year-old travel editor, returns from Morocco and becomes a close ally. When Jake asks Billie to profile Sal, she refuses, knowing Sal hates publicity. At Sammy's urging, she writes the story without permission, and Rosalie persuades Sal to allow publication.

In late October, Young Arthur Pickwick, the magazine's owner, abruptly shuts Delicious! down. Jake arranges for Billie to stay on alone in the mansion to honor the Guarantee, while Diana leaves for California. Isolated in the decrepit building, Billie contends with a worsening rotting smell. When Sammy returns from Istanbul, they discover the source: food abandoned in the locked kitchen. More importantly, Sammy finds a secret room behind a movable bookcase in the library. Inside are thousands of reader letters and a cache written by a twelve-year-old girl named Lulu Swan to James Beard, the legendary cook, during World War II.

Lulu's letters reveal her world: She is learning to cook for her exhausted mother, who works at a factory in Akron, Ohio, while her father, a fighter pilot, serves overseas. A December 1942 letter brings the devastating news that her father has been reported missing in action. Billie becomes consumed with finding more letters, which requires deciphering a treasure-hunt system embedded in the library's card catalog by its last librarian, known as "Bertie." Turquoise-ink entries contain clues leading from one batch to the next. Through successive discoveries, Lulu's wartime life unfolds: foraging for milkweed and morels, learning Italian cooking from her neighbor Mrs. Cappuzzelli, and crafting inventive meals from rationed ingredients.

Meanwhile, Sammy sinks into depression after losing his job prospects and his boyfriend. Billie, Thursday, and Richard stage an intervention by pretending to ruin a soufflé in his kitchen, knowing he cannot resist taking over. The ruse works. Sammy proposes a "mutual improvement pact" and begins helping Billie search for letters daily. Reading about a young soldier's death triggers an emotional collapse, and Billie finally tells Sammy the full story of Genie's death: The sisters ran a bakery called Cake Sisters, and Genie was struck and killed by a speeding car at a client's wedding while carrying the final cake tier. Billie has always believed the car was meant for her. Sammy tells her firmly it was a tragic accident.

Through research, they learn Bertie was Bertram Arnold Joseph Ancram, whose lifelong companion, Anne Milton, reveals that Young Arthur's predecessor ordered Beard's papers destroyed, possibly due to homophobia during the McCarthy era. Bertie hid the letters in the secret room, which he believed confirmed the mansion's history as a stop on the Underground Railroad, a network of safe houses that helped enslaved people escape to freedom before the Civil War.

When Pickwick puts the mansion up for sale, an architectural historian named Mitch Hammond arrives to assess the property. He turns out to be Mr. Complainer from Fontanari's. His growing attraction to Billie draws them together, and they share a first kiss in the mansion's basement beside a beehive oven, possibly the last of its kind in the city. Billie finds Lulu's final letter, dated Easter 1948, in which eighteen-year-old Lulu describes meeting Beard in New York, dining at Le Pavillon, a celebrated French restaurant, and walking through Little Italy, where she realizes the people buying food "weren't buying food: They were finding their way home" (275). Lulu reveals she still believes her father is alive.

When Mitch suggests that Genie's behavior sounds like cocaine use, Billie erupts in fury and flies alone to Ohio. She visits Lulu's childhood landmarks in Akron, then stops in Cleveland to see Mrs. Cloverly, who turns out to be an elegant cook named Babe who invented her hapless persona to combat loneliness. In Babe's pantry, Billie spots a box labeled "The Cleveland Cookshop, Lulu Taber, Proprietor." Her father, Bob Breslin, arrives unexpectedly, and together they track Lulu through library records and a sausage vendor at the West Side Market.

They find eighty-one-year-old Lulu, vigorous and direct, living in a large colonial house. She is initially hostile, ordering them to leave when Billie asks about her father. After Bob defuses the situation, Lulu agrees to see them again and reveals her secret: Five years earlier, she learned her father survived the war but chose to stay in France with the woman who saved his life. Lulu is furious rather than forgiving. That evening, Bob confirms what Mitch suspected: Genie had been buying cocaine for four years. Billie calls Mitch to apologize.

Returning to Lulu's house the next morning, Billie suffers a panic attack upon entering the kitchen but pushes through with Lulu's calm support. Lulu tells her that having a gift and turning your back on it is unforgivable. Billie recognizes it is time to stop running from cooking. She asks for ginger, flour, and spices, and bakes her gingerbread in Lulu's kitchen, whispering "No earthquakes now" (368) as she closes the oven door.

The novel closes with a final letter to Genie, written one year after Bob and Aunt Melba's wedding. Billie has opened Fontanari's Bakery at Sal's urging, and her pastries supply a restaurant opened by Jake and Maggie. Diana is returning to help with the bakery. Lulu visits often and has grown close to Sammy. Pickwick has decided not to sell the mansion, converting it into corporate headquarters. Anne Milton has died after completing the catalog of the Delicious! letters. Billie and Mitch plan to marry, and Billie writes that while she still mourns Genie, "every day brings a moment when I know that I am happy" (369).