Preheat your oven to 375°F (190°C). Line a large baking sheet with parchment paper to prevent sticking and for easy cleanup.

In a small bowl, whisk together the granulated sugar and ground cinnamon until they are thoroughly combined. Set this mixture aside.

Carefully unroll the can of crescent dough onto the prepared baking sheet. Do not separate the individual crescent triangles. Instead, press firmly along all the perforations to seal them together, forming one large, cohesive rectangle of dough.

Using a pastry brush (or the back of a spoon if you don't have one), evenly spread the melted butter over the entire surface of the crescent dough rectangle. Ensure the dough is well-coated.

Generously sprinkle the prepared cinnamon-sugar mixture over the buttered dough. Make sure the coating is as even as possible, reaching all edges of the dough.

Starting from one of the longer sides of the dough rectangle, carefully and tightly roll the dough into a log. Try to keep the roll as uniform in thickness as possible.

Using a sharp knife or unflavored dental floss, slice the rolled log into 16 even-sized rounds, approximately 3/4-inch thick. If using floss, slide it under the log, cross the ends over the top, and pull to cut cleanly. Arrange the slices cut-side up on the prepared baking sheet, leaving about 1 inch of space between each swirl to allow for expansion.

Bake the cinnamon-sugar crescent swirls for 10-12 minutes, or until they are puffed, golden brown, and cooked through. Keep an eye on them towards the end of the baking time to prevent over-browning.

Remove the baking sheet from the oven and let the swirls cool on the sheet for a few minutes before carefully transferring them to a wire rack to cool completely. Serve warm for the best experience, or at room temperature.