1. Preparing the Oven and Baking Sheets

Preheat your oven to 350°F (175°C). Line a large 15 in x 21 in baking sheet with parchment paper and set aside. If using two standard baking sheets, line both with parchment paper. Using a larger baking sheet allows all cookies to bake at once, ensuring they have shiny, crinkly tops.

2. Melting the Chocolate and Butter

In a microwave-safe bowl or double boiler, melt the unsalted butter and chopped dark chocolate together. Stir until completely smooth and set aside to cool slightly. This step is crucial as it combines the fats and chocolate flavors, forming the base of your brownie cookies.

3. Mixing the Dry Ingredients

In a medium-sized mixing bowl, whisk together the all-purpose flour, Dutch process cocoa powder, salt, and baking powder until well combined. This ensures an even distribution of the leavening agent and cocoa, resulting in a consistent texture and flavor.

4. Beating the Sugars, Eggs, and Vanilla

In a large mixing bowl, add the granulated sugar, light brown sugar, eggs, and vanilla extract. Using an electric mixer or stand mixer with a whisk attachment, beat the mixture on high speed for at least 7 minutes. This step is key to creating the signature crinkly top layer of brownie cookies by incorporating air into the eggs.

5. Combining Wet and Dry Ingredients

Once the sugar and egg mixture is pale and thick, gently fold in the melted chocolate and butter. Be careful not to overmix. Gradually add the dry ingredients to the wet mixture, stirring until just combined. The dough will be soft but thick, perfect for scooping.

6. Shaping and Arranging the Cookies

Immediately scoop the dough into 30 portions using a 1 tbsp capacity cookie scoop. Arrange the scoops on the prepared baking sheet, spacing them about 1 1/2 inches apart. It’s important to work quickly to maintain the shiny and crackly tops of the cookies.

7. Baking to Perfection

Bake the cookies in the preheated oven for 11-12 minutes, or until the tops have developed cracks and a glossy sheen. For a more uniform shape, use a circular cookie cutter to gently shape the cookies while they are still hot and soft.

8. Cooling and Finishing Touches

Let the cookies cool on the baking sheet for 5 minutes, allowing them to set slightly. Then, transfer them to a wire rack to cool completely. Sprinkle a pinch of flaky sea salt on each cookie while still warm for an extra burst of flavor.