1. Preheat the oven to 350°F and line two baking sheets with parchment paper.

2. Melt the semisweet chocolate chips and unsalted butter together in a heat-safe bowl until smooth, then let the mixture cool slightly.

3. In a separate bowl, beat the granulated sugar, brown sugar, and eggs until the mixture looks lighter and slightly thickened.

4. Stir in the vanilla extract and slowly mix in the melted chocolate mixture.

5. In another bowl, whisk together the all-purpose flour, cocoa powder, baking powder, and salt.

6. Fold the dry ingredients into the chocolate mixture just until combined.

7. Stir in the chocolate chunks.

8. Scoop the batter onto the prepared baking sheets, spacing the cookies apart.

9. Bake for 10 to 12 minutes, until the tops are crackly and the edges are set.

10. Sprinkle with flaky sea salt, let the cookies cool on the pan for 5 minutes, then transfer to a wire rack.