In a small bowl, combine the sugar and cinnamon. Stir until fully mixed.
Lightly flour a countertop and unfold the puff pastry. Spread the cinnamon-sugar mixture evenly over sheets, then sprinkle the chopped pecans on top.
Starting with the long edge, roll each sheet of puff pastry into a tight spiral. Once the sheet is fully rolled, pinch the seam together.
Using a sharp knife, cut the spiral into ¾” slices. Place each slice on its side on a parchment-lined sheet pan. Bake at 400°F for 13-15 minutes, or until golden in color.
Meanwhile, combine all of the ingredients for the icing in small bowl. Stir until smooth. Allow the cinnamon rolls to cool slightly before drizzling the icing on top. (Note: a sandwich bag with a corner snipped off makes a great tool for drizzling icing!)