St. Martin's croissant (Polish: rogal świętomarciński) is a croissant with white poppy-seed filling traditionally prepared in Poznań and some parts of Greater Poland region on the occasion of St. Martin's Day (11 November).

[3] In Poznań, the tradition of baking St. Martin's croissants on 11 November certainly existed in 1860, when the oldest known advertisement for the pastry was published in Dziennik Poznański.

The confectioner Józef Melzer, who was present at the mass and worked in a nearby confectionery, persuaded his boss to revive the old tradition.

[5] The wealthier Poznań residents bought the delicacy and the poor received it for free.

[5] The filling must, according to the protected designation documentation, consist of "white poppy seeds, sugar, crumbs, egg pulp, margarine, raisins, nuts, fruit in syrup or candied fruit".