Cinnamon Pinwheels

1 cup sugar
1/4 to 1/2 tsp cinnamon (to taste)
1 sheet frozen puff pastry (about 8 1/2 oz.), thawed but still cold

1. Mix the sugar and cinnamon together; dust work surface with half of it. Don’t unfold the puff pastry. Put it on the sugar and dust the top. Roll the dough, keeping sugar on both sides, into a 13-x-15-inch rectangle.
2. Brush off excess sugar and, starting from a short side, roll up the dough jelly-roll fashion. Cut 1/2-inch-thick slices and place them 2 inches apart on a parchment-lined baking sheet.
3. Bake at 350°F for 20 to 25 minutes, or until baked through to the center. Lift them off the sheet immediately and turn them over onto a clean sheet of parchment. Cool before serving.