6 egg whites (make sure to have NO egg yolk remnants in the egg whites or you will never get stiff peaks)
1/4 cup Dutch-process cocoa powder
1 1/4 cups sugar, divided
Pinch of kosher salt
Position 2 racks in the center of the oven and preheat to 250° F. Line 2 baking sheets with a silicone baking mat or parchment paper. Set aside.
Sift together the cocoa powder and 1/2 cup of the sugar into a medium bowl. Set aside.
Place egg whites in the bowl of a stand mixer fitted with the whisk attachment. Beat the egg whites on medium speed until very frothy, about 1 minute. Add a pinch of kosher salt and continue beating until soft peaks form, about 2-3 minutes. Increase the speed to high and begin to gradually add the remaining 3/4 cup of sugar, 1 tablespoon at a time, allowing sugar to fully incorporate between each addition, about 10 seconds. Once all the sugar has been incorporated continue beating until stiff peaks form, about 1-2 more minutes.
Sprinkle 1/3 of sugar/cocoa mixture over the egg whites. Using a rubber spatula, gently fold the sugar/cocoa mixture into the egg whites, being careful not to deflate the egg whites. Once the sugar/cocoa is fully incorporated, repeat with another 1/3, then the final 1/3 of the sugar/cocoa mixture.
Once all the sugar/cocoa is incorporated into the egg white mixture, transfer to a large pastry bag fitted with a star tip. Pipe meringues onto the prepared baking sheets in the formation of a ladylock, about 2 inches long. (You can get creative here and pipe any shape you like, really!) Space the meringues about 2 inches apart.
Bake until meringues are completely dry, about 2 1/2 hours. Transfer pans to wire racks to let them cool completely. Once cool, carefully lift off trays and place in an airtight container for up to 3 days.
Barely adapted from Essentials of Healthful Cooking by Williams-Sonoma