1-First, preheat your oven to 350°F (175°C) and line two rimmed baking sheets with parchment paper or silicone mats; give the parchment a light spray if you’re using it to prevent sticking. This setup ensures your cookies bake evenly and come off the sheets without a fuss.

2-Next, in a large bowl, whisk together the 3 cups of powdered sugar, 2/3 cup of Dutch Process cocoa powder, and 1/4 teaspoon of salt until everything is well combined. Then, whisk in 2 egg whites and 1 tablespoon of vanilla extract, beating just until the batter turns moist and thick, like fudgy brownie mix if it feels too thick, add more egg whites one at a time, up to 4 total. Gently stir in the 1 1/2 cups of bittersweet chocolate chips to keep that gooey texture intact.

3-Scoop the batter onto your prepared baking sheets into about 12 evenly spaced mounds per sheet, using a spring-release cookie scoop if you have one for neat portions. Bake for around 14 minutes, or until the tops look glossy and lightly cracked, then slide the parchment with the cookies onto wire racks to cool completely before removing them this step is crucial to avoid breaking the delicate treats. You’ll end up with approximately 24 cookies that are ready to enjoy, with a total prep time of 25 minutes, cook time of 14 minutes, and overall time of about 39 minutes.