In a small bowl, whisk together sugar and cinnamon.
Scoop the chilled dough by tablespoonful, and drop one-by-one into cinnamon-sugar mixture. The dough will be fairly sticky.
Coat the balls thoroughly with cinnamon-sugar.
Flatten into disks, about 2 inches in diameter, and recoat with cinnamon-sugar. The first coat helps make the balls easier to handle, and the second coat just adds extra snickerdoodle!
Place over the pumpkin filling, overlapping them slightly.
Bake at 350 degrees for 35-40 minutes, or until the edges are golden brown, and the center appears set when jiggled.
Remove to a wire rack to cool for 10-15 minutes.
Cut and serve warm with whipped cream.