474 Columbus Avenue, San Francisco
Z. Cioccolato, founded in 2003, makes their distinctive big fudge in a multitude of flavors, such as 7-layer peanut butter fudge, at their shop in North Beach. In addition to classics like plain milk chocolate and unique California themed flavors like CA Earthquake (walnuts and coconut) they are always developing new flavors, so there is always something to look forward to.
You can order their fudge and other candy treats online. They also offer chocolate making classes.