01 - Preheat oven to 350°F and line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together flour, baking powder, baking soda, salt, matcha powder, cinnamon, and nutmeg.
03 - In a large bowl, beat softened butter, granulated sugar, and brown sugar until pale and fluffy.
04 - Blend in the egg and vanilla extract until mixture is smooth.
05 - Incorporate pumpkin puree, mixing until uniform.
06 - Gradually stir dry ingredients into the wet mixture just until combined, avoiding overmixing.
07 - If desired, fold in white chocolate chips or chopped nuts.
08 - Using a cookie scoop or tablespoon, drop approximately 2 tablespoons of dough per cookie onto prepared sheets, spacing 2 inches apart.
09 - Bake for 13–15 minutes, until cookies are set and edges are lightly golden.
10 - Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.