Start by preheating your oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a microwave-safe bowl, combine the semi-sweet chocolate chips and cocoa powder. Microwave in 30-second intervals, stirring in between, until the chocolate is melted and smooth. Allow it to cool slightly.
In a mixing bowl, whisk together the granulated sugar, brown sugar, eggs, and vanilla extract until well combined.
Add the melted chocolate mixture to the sugar and egg mixture, stirring until fully incorporated.
In a separate bowl, combine the baking powder, salt, and flour. Gradually mix the dry ingredients into the wet ingredients until a dough forms.
Let the dough rest for about 10 minutes to firm up slightly.
Using cookie scoops or two spoons, drop rounded tablespoons of dough onto the prepared baking sheet, ensuring spaces are left between each cookie.
Generously dust each cookie ball with powdered sugar; this will create the signature crinkle effect.
Bake in the preheated oven for 10-12 minutes, or until the cookies have puffed up and the tops look crinkled.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.
Notes
Allow the cookies to cool completely for the best texture.