Obviously, Ng is a sugar addict, but she also is clever about food, says friend and journalist Eric Simons. She's been known to throw interesting food parties, such as an annual Halloween book club gathering where she usually chooses a zombie book and serves brain-themed foods.

As part of her "31 Flavors" project, Ng vowed to create 31 flavors of ice cream in the year before her 31st birthday in May (she's completed No. 30, an Asian pear-green tea sorbet and started No. 31: horchata with snickerdoodles).

Her favorites so far include strawberry candied jalapeno (a nod to San Francisco's Humphry Slocombe); goat cheese ice cream with caramelized figs and candied bacon (inspired by a Jeni's Splendid Ice Cream in Columbus, Ohio); and celery ice cream with rum-plumped raisins and a peanut butter swirl (modeled after the childhood combination of celery sticks, peanut butter and raisins).

"There are a billion things you can do with ice cream, but she's really good about finding different flavors of ice cream, different preparations, and different people who make it with different cultural backgrounds," Simons says. "It turns out to be intellectually interesting."

Ng will serve up ice cream trivia in the book, including the story of how William Dreyer gave an ice cream made with chocolate, nuts and marshmallows the name Rocky Road to cheer up Great Depression-era Americans. Or how Ben Coen's lost sense of smell led to Ben & Jerry's signature chunkiness as he sought additional texture.

She'll also delve into some of the cultural differences surrounding ice cream. In Buenos Aires, where gelato, or helado, is commonplace due to the flow of 19th century Italian immigrants, ice cream is enjoyed while lounging with friends and family late at night after dinner, Ng says. In the Philippines, ice cream is often picked up and consumed at home.

Ng will include in the book a map of San Francisco, which she says stands out for ingredients that are high quality, local and seasonal. Those traits are evident at places like Smitten Ice Cream, which features a seasonal flavor of the month, such as Meyer lemon gingersnap or rhubarb crisp.

We asked Ng for recommendations at some of San Francisco's top ice cream shops. Outside San Francisco, she's keen on Fenton's in Oakland, Real Ice Cream in Santa Clara and Sunnyvale, Ici Ice Cream in Berkeley, Tara's Ice Cream in Oakland and Berkeley, Fairfax Scoop in Fairfax and Three Twins in Napa.

Bi-Rite Creamery: Many people know this Dolores Park hotpot for its salted caramel, but Ng really loves the Dainty Gentleman Sundae, made with olive oil and sea salt, which she says adds silkiness and draws out sweetness. She also recommends balsamic strawberry ice cream when it is in season, along with Bi-Rite's seasonal popsicle.

Bi-Rite Creamery's Dainty Gentleman Sundae with honey lavender ice cream, hot fudge, blood orange olive oil and Maldon sea salt. Photo: Tilde Herrera — Bi-Rite Creamery's Dainty Gentleman Sundae with honey lavender ice cream, hot fudge, blood orange olive oil and Maldon sea salt.

Humphry Slocombe: Ng says this joint isn't your typical ice cream shop. You'll find Warhol-inspired art and flavors that range from the familiar to the eyebrow-raising, including banana, carrot and bacon. Ng recommends the Thai chili lime sorbet and the Harvey Milk and honey, made with honey and graham crackers.

Humphry Slocombe's Thai chili lime sorbet. Photo: Tilde Herrera — Humphry Slocombe's Thai chili lime sorbet.

Ice Cream Bar: This ice cream and soda fountain parlor offers lots of seating space, Ng says, making it ideal for parties. She recommends the Tropical Split (ask for a similar sundae if it's not in season) and the Hamilton, especially with basil ice cream and fresh strawberries.

The Hamilton at Ice Cream Bar, made with a spoonful of ice cream, lemon, malt, fountain syrup and soda. Photo: Tilde Herrera — The Hamilton at Ice Cream Bar, made with a spoonful of ice cream, lemon, malt, fountain syrup and soda.

Mitchell's Ice Cream: This San Francisco institution is known for exotic and tropical flavors such as avocado, ginger, horchata, jackfruit, lucuma and macapuno (coconut from the Philippines). Ng calls Mitchell's a great example of business owners adapting their offerings to the demographics of their customers.

A scoop of ube -- purple yam imported from the Philippines -- and the Tropical 4, a mango, guava, banana and pineapple combo at Mitchell's. Photo: Tilde Herrera — A scoop of ube -- purple yam imported from the Philippines -- and the Tropical 4, a mango, guava, banana and pineapple combo at Mitchell's.

Mr. and Mrs. Miscellaneous: The menu changes everyday -- and sometimes during the day -- but this Dogpatch shop always offers 10 flavors. Ng suggests asking for staff recommendations on a house-made cone. Ng admires the consistency in quality and texture, noting that here the ice cream is kept much colder than at other ice cream shops.

Butter toffee and burnt sugar ice creams on a house-made cone at Mr. and Mrs. Miscellaneous. Photo: Tilde Herrera — Butter toffee and burnt sugar ice creams on a house-made cone at Mr. and Mrs. Miscellaneous.

Smitten Ice Cream: This tiny ice cream shop located in a shipping container in Hayes Valley uses liquid nitrogen to make its ice cream on the spot. Among its offerings: two classic flavors, two seasonal scoops and vegan Popsicles.

Ng recommends one of Smitten Ice Cream's seasonal flavors; March is blood orange with pistachio shortbread. Photo: Tilde Herrera — Ng recommends one of Smitten Ice Cream's seasonal flavors; March is blood orange with pistachio shortbread.

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