Combine the butter and sugar in the bowl of a stand mixer (or in a large bowl, and use an electric mixer) and beat together until ingredients are well-creamed.
Add eggs, one at a time, stirring until completely combined, and then stir in vanilla extract.
In a separate bowl, whisk together the flour, cocoa powder, baking powder, and salt.
Gradually add dry ingredients to your wet ingredients until completely combined.
Cover bowl with plastic wrap and refrigerate at least 4 hours or overnight.
After chilling, preheat oven to 350F (175C) and prepare baking sheet by lining with parchment paper.
Roll dough into 1½ Tablespoon-sized balls and roll thoroughly in powdered sugar.
Transfer to baking sheet and bake on 350F (175C) for 10-12 minutes -- take care to not over-bake.
Within 1-2 minutes of removing cookies from oven, gently press a chocolate kiss into the center of each cookie.
Allow cookies to finish cooling completely on baking sheet before enjoying.