In a medium bowl, whisk together the flour, baking soda, salt, cinnamon, and nutmeg.

In a large mixing bowl, combine melted butter, brown sugar, and granulated sugar until smooth. Mix in pumpkin puree, maple syrup, vanilla extract, and egg yolk.

Gradually add the dry ingredients to the wet ingredients, stirring until just combined.

Cover the dough with plastic wrap and refrigerate for 30 minutes.

Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.

Once chilled, scoop the dough into 1½ tablespoon balls and place on baking sheets, spaced 2 inches apart. Bake for 10-12 minutes.

Let the cookies cool on the baking sheet for 5 minutes before transferring to a wire rack.