**Cream butter and sugar** In a mixing bowl, beat the softened butter and sugar on medium speed until light and fluffy, about 2–3 minutes.

**Add egg and vanilla** Beat in the egg and vanilla extract, scraping down the sides of the bowl as needed.

**Combine dry ingredients** In a separate bowl, whisk together the flour, cocoa powder, baking powder, and salt.

**Form the dough** Gradually stir the dry mixture into the creamed butter and sugar. Mix just until combined; do not overmix.

**Chill the dough** Divide the dough into two portions. Wrap each in plastic wrap and refrigerate for at least 1 hour (or up to overnight) to make rolling easier.

**Preheat oven** Preheat your oven to 350°F (175°C). Line baking sheets with parchment paper or silicone baking mats.

**Shape or cut cookies** On a lightly floured surface or between sheets of parchment, roll out the chilled dough to about 1/4-inch thickness. Cut into desired shapes or roll into 1-inch balls and flatten slightly. Place cookies on prepared baking sheets, spacing them about 2 inches apart.

**Bake** Bake for 8–10 minutes, or until the edges are set. Cookies will still appear slightly soft in the center. Allow them to cool on the baking sheet for 2 minutes before transferring to a wire rack to cool completely.