After that scoop of Ben & Jerry's this Saturday, foodies can flock to the Union Square Macy's (170 O'Farrell at Powell) cellar for another freebie. At 2 p.m., Delfina executive chef (and ahem! James Beard Award winner) Craig Stoll and pastry chef Koa Duncan will demo and offer tastes of "summer flavors": fresh stretched mozzarella and buttermilk panna cotta. The Delfina panna cotta -which Michael Bauer recently said he "can't forget"-- is a serving of culinary wonder: creamy, fresh, and delicately sweet. Stoll and Duncan are a part of the upcoming SF Chefs.Food.Wine festival, which is a sponsor of the Macy's event. The event is likely meant to get foodies salivating for more: SF Chefs.Food.Wine will run August 6-9 in the Bay Area, with varying events and price points.