On Sept. 26, Millennium hosted a 30th Anniversary celebration. The cheerful staff buzzed around the dining room refilling drinks, chatting and catching up with old friends. A former dishwasher played in the music trio in the corner. Diners arrived dressed to the nines, eager to sip wine and sample the hors d’oeuvres. At the front of the restaurant, the small bites disappeared as quickly as they arrived. Lettuce wraps contained the unlikely combination of clamshell mushrooms, gigantes beans and avocado. I would have subtracted the mushrooms and added some crunch. Radish, perhaps, or a bell pepper. An encrusted ball of arancini, with corn miso butter and a puttanesca sauce, proved to be a substantial dish that complemented the more ephemeral ones. Thirty years ago, vegan and vegetarian restaurants were culinary outliers. For confirmed carnivores and omnivores, they promised tofu-forward meals covered in alfalfa sprouts and served with butterless brown bread. Millennium executive chef and co-owner Eric Tucker understood that a plant-based menu appealed to a niche audience. But as the benefits of plant-based diets gained traction in the ensuing years, Millennium developed a following among vegans and non-vegans alike. Nowadays, Tucker describes the cuisine he makes as “California casual.” The meals are seasonal, and the menu changes regularly. “We’re pretty much an old-school restaurant with appetizers and entrées,” he said. Tucker believes Millennium diners appreciate the fact that the kitchen resists the use of fake meat products. “You’re going to see a potato cake sitting over a bunch of lobster and oyster mushrooms,” he said. “You might get the suggestion of seafood because it’s got a little sea-bean salad with nori dust.” People also appreciate the restaurant’s farm-to-table approach. “We were one of the first ones to go to farmers’ markets to buy produce directly from farmers,” Tucker said. The chef attributes the restaurant’s longevity, in part, to a range of special events. “As far as I know, we’re still the only restaurant that does an all-chili-pepper tasting menu,” he said. And, in August, the restaurant hosted an all-tomato dinner. Millennium was reborn from the ashes of Margaret Malone’s San Rafael restaurant, Milly’s. In 1990 Tucker secured an internship there through his culinary program, and loved the vibe. After Malone closed Milly’s a couple of years later, Tucker found investors to restart the restaurant with a new moniker in San Francisco. Millennium moved to its current Rockridge location in 2015. Before Alison Bagby began at Millennium in 2007, she had decided she was finished working in the restaurant business. By the time she moved to San Francisco, Bagby had already worked at upscale plant-based restaurants in Portland and Los Angeles. “I was moving in a different direction, but I saw that Millennium was hiring,” she said. She felt that the restaurant served the best food of its kind in the country. Bagby is now Millennium’s director of operations and co-owner. She believes a crucial element of the restaurant’s enduring success is chef Tucker’s menu, inspired by cuisines from around the globe. “Eric’s creative talent as an amazing chef is underappreciated,” she said. “There aren’t many restaurants where you can choose something Italian, or South American. You have so many flavor profiles on the menu that satisfy a lot of people.” Longtime guests tell her the food continues to get better and better. The 30th Anniversary celebration offered an opportunity for friends and family members of Millennium’s staff to gather with a devoted community. For many years, Bagby’s kids spent time in the restaurant while she worked 14-hour shifts there. Miyoko Schinner, vegan chef and cookbook author, showed up, too, which was one of the highlights of the party for Bagby. “There was a lot of appreciation for the restaurant in one room,” Bagby said. “We don’t have a lot of employee turnover, and it feels like a kind of family. We’re lucky to have the people we work with.” Millennium, open Tue-Sat, 5-9pm. 5912 College Ave., Oakland. 510.735.9459.  millenniumrestaurant.com. IG: @millenniumrestaurant.