Tennant can probably confirm, but I believe there was an episode this season wehn Mona brought back Salt Water Taffy. Ross has it at Central Perk and offers some to Phoebe, who claims she has never had it before.
However, in the beginning of TOW the Chicken Pox, Phoebe says someone tips her while she is playing at Washington Square Park, but didn't have money, so he tipped her with Salt Water Taffy.
Why didn't she try it then if she had never had it before, ya know?