Start by combining the wet ingredients. Whisk together melted butter, brown sugar, granulated sugar, vanilla, and pumpkin puree until smooth.
Mix the dry ingredients. In a separate bowl, whisk flour, salt, baking powder, baking soda, cinnamon, and pumpkin pie spice.
Combine wet and dry ingredients. Add the wet mixture to the dry ingredients and stir until a soft dough forms. If desired, fold in white chocolate chips.
Chill the dough. Cover and refrigerate for at least 30 minutes, or up to 3 days for best flavor and texture.
Prepare for baking. Preheat the oven to 350°F and line baking sheets with parchment paper.
Shape the cookies. Scoop dough into balls, roll in cinnamon sugar, and place on baking sheets. Flatten slightly for even baking.
Bake until set. Bake for 11-12 minutes until the edges are firm but centers are soft. Optionally, press extra white chocolate chips on top for decoration.
Cool and enjoy. Allow cookies to cool on the baking sheet before transferring to a wire rack. Cookies develop more flavor and chewiness as they cool.