Roll pastry to a 12- x 6-inch rectangle, and spread with butter. Combine sugar and cinnamon; sprinkle mixture over rectangle. Roll up jellyroll fashion, beginning at long side; moisten edges with water to seal. Cut into 1/3-inch slices; place slices, cut side down, in a greased 8-inch round cake pan.
Bake at 400° for 12 minutes or until pastry is flaky and lightly browned. Serve warm.