Preheat oven to 350 degrees. Line a large 15 in x 21 in baking sheet with parchment paper and set aside.

Melt the butter together with the chopped dark chocolate. Set aside to let it cool slightly.

In a medium sized bowl, whisk together the all-purpose flour, cocoa powder, salt, and baking powder. Set aside.

In a large bowl, add the granulated white sugar, light brown sugar, eggs, and vanilla. Beat the ingredients on high for at least 7 minutes.

Mix in the melted chocolate and butter.

Add the dry ingredients to the wet ingredients. Mix until just combined; the dough will be very soft.

Scoop the dough into 30 portions using a 1 tbsp capacity scoop onto the prepared baking sheet, arranging them about 1 1/2 inches apart.

Bake for 11-12 minutes until the tops have cracked. Use a circular cookie cutter to give them a more circular shape if desired.

Let the cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to finish cooling. Sprinkle with flaky sea salt and serve.