Heat oven to 400°. Spray 2 cookie sheets with cooking spray. Unfold pastry on lightly floured surface. Roll into 12-inch square, trimming edges to make even. Cut into 6 rows by 6 rows to make 36 (2-inch) squares. Place on cookie sheets. Bake 12 to 15 minutes, rearranging cookie sheets after 6 minutes, until puffed and golden brown. Remove from cookie sheets to wire rack. Cool until slightly warm.