Preheat the Oven:
Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

Prepare the Dough:
In a medium bowl, whisk together the flour, cocoa powder, baking powder, and salt. In a separate large bowl, beat the melted butter, granulated sugar, and brown sugar together until smooth. Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract. Gradually mix in the dry ingredients until combined.

Chill the Dough:
Cover the dough with plastic wrap and refrigerate for at least 2 hours (or overnight if you prefer). This step helps the dough firm up and makes it easier to roll.

Form the Cookies:
Once chilled, scoop tablespoon-sized portions of dough and roll them into balls. Roll each dough ball generously in powdered sugar, ensuring it’s fully coated.

Bake the Cookies:
Place the dough balls about 2 inches apart on the prepared baking sheet. Bake for 10-12 minutes, or until the edges are set but the centers are still soft. Let the cookies cool on the baking sheet for a few minutes, then transfer them to a wire rack to cool completely.

Serve:
Serve these delightful cookies with a glass of milk, hot chocolate, or your favorite warm beverage!