Preheat the oven to 350 degrees. Line a baking sheet with parchment paper, or a silicone liner.
In a medium bowl, whisk together the dry ingredients, the flour, cocoa powder, baking powder, and salt. Set the mixture aside. 1 1/2 cups all purpose flour, 1/2 cup unsweetened cocoa powder, 1/2 tsp baking soda, 1/2 tsp baking powder, 1/2 tsp salt
Using a large bowl with a hand mixer, or a stand mixer, cream together the butter and sugars for a couple minutes until light and fluffy. 1/2 cup unsalted butter, 1/2 cup granulated sugar, 1/2 cup brown sugar
Add in the egg, and vanilla extra and stir until just combined. Scrape the bottom and sides of the bowl as needed. 1 large egg, 1 tsp vanilla extract
Add the dry ingredients to the wet ingredients and mix on slow speed until combined. Add in the milk if needed, if the dough is too dry. 1 TBS milk
Scoop the dough into 1 TBS portions and roll them into balls. Roll the balls into the remaining sugar. 1/4 cup granulated sugar
Place them onto the prepared baking sheet, 2 inches apart from each other.
Bake the cookies for 6 to 8 minutes, until the tops are just barely set.
Remove the cookies from the oven and gently press a chocolate kiss into the cookie. Don't push it down hard or the cookie will break. 36 chocolate kisses
Let the cookies cool on the baking pan for 10 minutes, then transfer them to a wire cooling rack to cool completely.