Nancy Passaretti is revamping the fro-yo fad with Buddhaberry, her frozen yogurt shops in Sag Harbor and Montauk that offer all natural yogurt with superfood toppings, as well as an entire spectrum of sweets. After last season, her first summer with Buddhaberry in Montauk, Ms. Passaretti decided to move to the South Fork full time and open a year-round store at 125 Main Street in Sag Harbor.