Roll pastry into a 12- x 8-inch rectangle on a lightly floured surface.
Combine butter, sugar, and cinnamon; mix well. Brush over surface of pastry, leaving a 1/2- inch margin on all edges. Moisten edges with water; fold dough in half lengthwise. Press pastry edges together using a fork dipped in flour.
Transfer to a lightly greased baking sheet. Bake at 450° for 8 minutes or until golden brown. Cool slightly, and cut into 1/2- inch slices.