01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - Whisk flour, cocoa powder, baking powder, baking soda, and salt in a medium bowl.
03 - Beat softened butter and granulated sugar in a large bowl until light and fluffy, about 2 minutes.
04 - Add egg and vanilla extract to butter mixture. Beat until well combined.
05 - Gradually add dry ingredients to wet ingredients, mixing just until incorporated.
06 - Scoop tablespoon-sized portions, roll into balls, and place 2 inches apart on prepared baking sheets.
07 - Flatten each dough ball slightly with the bottom of a glass.
08 - Bake for 9-11 minutes, until edges are set and centers look slightly soft.
09 - Cool on baking sheets for 5 minutes, then transfer to a wire rack to cool completely.
10 - Dust with powdered sugar and decorate with festive sprinkles if desired.