Preheat the oven to 350°F (180°C).
Line a baking sheet with parchment paper.
Cream the butter and sugar until light and fluffy.
Add the egg yolk and vanilla extract, mixing until well combined.
Mix in the pumpkin puree until smooth.
In a separate bowl, whisk together the flour, pumpkin pie spice, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until a dough forms.
Roll the dough into balls, about 1 inch in diameter.
Roll each ball in a mixture of granulated sugar and pumpkin pie spice to coat.
Place the balls onto the prepared baking sheet, leaving about 2 inches of space between each cookie.
Bake for 10-14 minutes, or until the edges are lightly golden brown.
Remove from the oven and let cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.