Preheat your oven to 350°F (175°C). Line two baking sheets with parchment paper.
In a microwave-safe bowl, melt the chocolate chips and butter in 20-second intervals, stirring after each until smooth. Set aside to cool slightly.
In a large bowl, whisk together granulated sugar, brown sugar, eggs, and vanilla extract until light and fluffy.
Gradually mix the melted chocolate into the sugar mixture until well combined.
Sift together the flour, cocoa powder, baking powder, and salt. Fold these dry ingredients into the wet mixture until just combined. Do not overmix.
Optional: Stir in chopped nuts or extra chocolate chips for added texture.
Scoop tablespoons of dough onto the prepared baking sheets, spacing them 2 inches apart.
Bake for 10-12 minutes, or until the edges are set, and the tops have a crinkle effect. The centers should remain slightly soft.
Allow cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.