In a large mixing bowl, sift the flour and cocoa powder together then whisk in the baking powder and salt. Set aside.
In a separate mixing bowl, whisk together the melted butter, granulated sugar, and brown sugar until well combined. Mix in the eggs and pure vanilla extract until fully combined.
Add the dry ingredients to the wet ingredients and mix together until just combined.
Cover tightly and refrigerate for at least 2 hours.
Meanwhile, preheat the oven to 350°F (177°C). Line large baking sheets with parchment paper or silicone baking mats. Add the powdered sugar to a small bowl and set aside.
Remove the cookie dough from the refrigerator. Using a 1.5 tablespoon cookie scoop, scoop the cookie dough, roll in the powdered sugar, and place onto the prepared baking sheets. Repeat with the remaining cookie dough.
Bake for 11 to 13 minutes or until the tops of the cookies are set. Remove from the oven and allow the cookies to cool on the baking sheets for 5 to 10 minutes, then carefully transfer the cookies to a wire rack to cool completely.