A star pastry chef goes home to Oahu with a food-writer pal and returns to San Francisco with ideas for great new desserts.

The first time my best friend, Heather Ho, and I drove past Keo's Thai Cuisine in our hometown of Honolulu, I asked her, "What is thigh cuisine?" We were 16 then, but she still loves to embarrass me with this story.

Heather has always known more about food than I have. She started reading cookbooks at age eight and graduated from the Culinary Institute of America at 24. I'm a food writer; she's the pastry chef at Boulevard restaurant in San Francisco. Reviewers swoon over her updated American classics: lemon icebox cake with huckleberries, banana-bread-and-butter pudding, butterscotch crème brûlée served with devil's food cake.

Recently, the two of us returned to Oahu; it is the first time we've been home together since we were in college, nearly a decade ago. Heather needed a breather from her 12-hour days, and she wanted to sample the desserts we grew up on to see if they might inspire her. I'm here because I couldn't imagine anything more fun than driving around Oahu eating nothing but sweets with my best friend.

Hawaiian desserts reveal a lot about the different cultures on the islands. Many of the recipes are Asian in origin, since about 60 percent of Hawaiians are of Asian descent. Although intermarriage means many people are a mix of ethnicities, the islands' cuisines have remained true to their roots. And the desserts have kept the minimalism that makes them characteristically Asian.

Heather's roots are Chinese. Her father's family came to Hawaii from Guangdong in the 1870s. One of her earliest memories is of the three-generation Ho family dinners that took place every Sunday at a local Chinese restaurant. Her grandfather, Chinn Ho, a prominent local businessman, would order the dishes: things like chicken-feet soup and swamp cabbage with fish sauce. "He never ordered the kind of food that appealed to children," Heather recalls, "so by the time dessert came around, I was always starving." Her favorite childhood dessert was peanut soup with mochi balls (rice flour dumplings) stuffed with lotus seeds.

Although her grandfather's neighborhood restaurant has long since closed, Heather and I have found another place, Legend Seafood Restaurant, that does a convincing rendition of the peanut soup. Legend is a large dim sum parlor that is filled at lunchtime with businesspeople making deals in Cantonese and Mandarin. We order the soup (usually available only at dinner), and it's as wonderful as Heather remembers--sweet, warm and velvety. A quick discussion with the manager explains why: The kitchen staff hand mills the peanuts for the soup.

The next night we return for the first time in a decade to Keo's, which still serves the dessert that Heather obsessed about as a teen: apple bananas in Thai tapioca. The tapioca, soupier and whiter than the gloppy cafeteria version we were subjected to in school, is topped with coconut milk and slices of steamed apple banana, a short, plump variety used in this dish while still green. The tart-sweet apple banana is a perfect foil for the rich coconut milk and silky-springy tapioca pearls. (Heather can't stop thinking about that tapioca, and soon after our trip she'll include it on the menu at Boulevard. Her creation: a mango cheesecake topped with a coconut-tapioca sauce. "I had wanted to make tapioca ice cream, but the pearls froze. Their consistency works better as a sauce," she says.)

The next day, as the mid-morning sun beats down on us, we are ready for the beach. The heat reminds us why shave ice is so popular here, and in our minds, there's only one place to get it--the North Shore, where waves the size of apartment buildings have attracted surfers for generations. On this windblown tip of the island, Heather and I used to swear by this ritual: lunch at Kua Aina, a local burger joint; a dive off the rocks into Waimea Bay and some lolling about on Sunset Beach; then a stop at Matsumoto's for shave ice.

Housed in a clapboard building with a corrugated metal roof that's probably held together only by 50 years' worth of paint, M. Matsumoto Grocery Store has looked the same since I was four and my family would stop there on the way home from my uncle's surf meets. (He was world champion in the late Sixties.) Heather and I dig into Matsumoto's signature shave ice: a white paper cone lined with Japanese adzuki beans and vanilla ice cream, then covered with ice the consistency of fresh fallen snow, which we order flavored with strawberry, pineapple and lilikoi (passion fruit) syrups. We plunge our spoons down deep to get a mix of beans, ice cream and flavored ice all at once. We usually end up sticky with syrup, but it's worth the mess.

Then we get a hot tip from the "coconut wireless" (what our Hawaiian grandmothers called the grapevine): Haili's Hawaiian Foods sells a haupia--a coconut-flavored cross between gelatin and custard served as a cold white square, a traditional luau dessert--that's not to be missed. Nothing more than a take-out stand in the Ala Moana farmers' market, Haili's is a family-run operation with staffers who cheerfully dish out grandmother Rachel's 50-year-old recipes. As we step out into the sunlight from the dark, low-slung cover of the market, Heather takes a bite of the haupia and smiles. It is perfect: the mix of creaminess and firmness, the purity of the fresh coconut. She muses about how lovely it would be incorporated into a frosting for a buttery yellow layer cake. (Weeks later she will be in the kitchen at Boulevard, testing her version of haupia cake--to the raves of her fellow chefs.)

On our last day, we eat 12 desserts and call it quits--at least I do. After one last malasada, an airy Portuguese donut, from Leonard's bakery, I insist that we stop. Heather, ready to keep eating, begins planning how to memorialize the trip at Boulevard. Her customers won't know it, but this summer, when they bite into her new desserts, they may be tasting the sweet comfort of a Hawaiian childhood.

Malia Boyd is a freelance writer who lives in New Orleans.