On St. Patrick's Day or thereabouts Arby’s is introducing a Mint Chocolate Swirl Shake; Smashburger has introduced a Mint Oreo Shake as a seasonal limited-time offer, available through June. Cinnabon has introduced an Oreo Mint Chillatta. Einstein Bros. Bagels is offering green bagels from March 15-17, as well as Shamrock Sugar Cookies topped with green icing.