Blot the pumpkin: Spoon the pumpkin puree onto 3 to 4 layers of paper towels. Press firmly with fresh paper towels repeatedly until a fresh sheet comes away with only a faint stain — not visibly wet. Measure 130g / ½ cup of blotted puree and set aside.

Whisk flour, baking soda, pumpkin pie spice, cinnamon, and salt in a medium bowl. Set aside.

Beat softened butter and packed brown sugar on medium speed for 3 minutes until the mixture is smooth and slightly fluffy.

Add the blotted pumpkin puree, egg yolk, and vanilla extract. Beat for 20 to 30 seconds until just combined. The mixture may look slightly curdled — this is normal.

Add the flour mixture all at once. Mix on low speed until just combined — stop the moment you no longer see dry flour streaks.

Cover the dough tightly with cling film pressed directly onto its surface. Refrigerate for at least 30 minutes (1 hour recommended).

Preheat oven to 175°C / 350°F (160°C fan). Line two baking sheets with parchment paper. Stir together the granulated sugar and cinnamon in a small bowl.

Scoop dough into 1½-tablespoon balls. Roll between palms until smooth, then roll in cinnamon sugar to coat fully. Place 5cm / 2 inches apart on the prepared trays.

Bake one tray at a time on the centre rack for 11 to 13 minutes, until the edges are set and the centres still look slightly underdone.

Cool on the baking sheet for 5 minutes, then transfer to a wire rack. Cool completely before storing.