O, Justin: The long wait for fans of Restaurant O is over. Chef Justin Perez has transformed his catering operation -- located on the Santa Clara site that was home to the beloved Wilson's Jewel Bakery -- into Justin's, an ambitious restaurant and catering-events operation. With Justin's, he and business partner Wesley Byers aim to capitalize on the following they developed in Campbell with Perez's vibrant menus. And we're talking long menus. The entrees alone number 24, and those include Perez's signature osso buco (braised in cabernet, served with saffron risotto and gremolata) and his pan-roasted elk chop (with a savory blueberry sauce). In 2007, then-Mercury News critic Aleta Watson dubbed those his "greatest hits" and bestowed 3.5 stars on Restaurant O. His new menu also offers nine side dishes (cauliflower flan with crushed pepperoncino, Japanese risotto eggplant sticks); several sushi-style rolls (miso-glazed crispy pork belly and Asian pear); long lists of appetizers and desserts; plus lunch salads, sandwiches and pizzas topped with wild boar sausage or braised lamb. Even the burger menu is unusually ambitious: Not only do you get to choose either a beef, turkey, elk or vegetarian patty, but you also get to select how you want your burger cooked -- broiled, grilled or pan-seared.

Details: 1285 Homestead Road, Santa Clara. 408-638-5300; www.chefjustinperez.com. Open 11 a.m.-10 p.m. Tuesday-Saturday.

On the Peninsula: Speaking of hamburgers, L.A.-based Umami will throw open the doors of its new Palo Alto outpost at noon Friday. The eatery's "exclusive" burger -- each location has a specially crafted one -- will be revealed then. (San Francisco's is a bacon-wrapped scallop burger, for example, and in Hollywood, you can order a beef burger with pastrami.) The classic creations available at all sites include the Umami, with shiitake mushrooms, caramelized onions and roasted tomato; and the port and Stilton burger. Details: 452 University Ave., Palo Alto. www.umami.com.

Send your South Bay and Peninsula restaurant tips to Linda Zavoral, lzavoral@mercurynews.com.