Preheat oven to 350°F. Line two baking sheets with parchment paper.
In a medium bowl, whisk together flour, cocoa, baking powder, salt, and baking soda.
In a large bowl, whisk together brown sugar, granulated sugar, eggs, and vanilla.
Combine the butter and chocolate over a double boiler until the butter and chocolate are melted and well combined. Add the chocolate mixture to the sugar-egg mixture. Mix until well combined. Add flour mixture and mix with a spatula until combined.
Place the powdered sugar in a medium bowl. Using an ice cream scoop, drop dough portions into the powdered sugar and gently roll. Cover the dough portions completely with powder sugar. Place six cookies per prepared pan.
Place in the oven and bake for 15 minutes for soft chewy in the inside cookies or 18-20 minutes for a firmer cookie. Remove from the oven and let the cookies cool down on the pan for 5 minutes. Transfer cookies to a cooling rack.