Mix Dry Ingredients: In a medium bowl, whisk together the cocoa powder, flour, baking powder, and salt. Set aside.

Cream Butter + Sugar: In a large bowl, beat the softened butter, granulated sugar, and vanilla until combined.

Add Eggs: Add the eggs one at a time, mixing on medium-low speed just until incorporated, about 10 seconds per egg.

Combine: Add the dry ingredients to the wet mixture and mix on low speed until fully incorporated.

Chill the Dough: Cover the bowl and refrigerate the dough for at least 1 hour or up to overnight. Longer chilling results in thicker cookies.

Prep to Bake: Preheat oven to 350°F (177°C). Line baking sheets with parchment paper. Place powdered sugar in a medium bowl.

Roll: Scoop heaping tablespoon-sized portions of dough and roll into balls. Roll each ball generously in powdered sugar.

Bake: Place cookies 2 inches apart on prepared baking sheets. Bake one sheet at a time for 8–12 minutes, until spread and crackled.

Add Kisses: Remove cookies from the oven and immediately press a chocolate kiss into the center of each cookie.

Cool: Let cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely. Do not touch the chocolate kiss until fully set.