Preheat your oven to 250°F (120°C) and line two baking sheets with parchment paper.

Ensure your mixing bowls and beaters are clean and free from grease.

Beat the egg whites on medium speed until foamy, add salt and continue until soft peaks form.

Gradually add granulated sugar, one tablespoon at a time, until stiff, glossy peaks form.

Sift in cocoa powder and gently fold it into the meringue.

Add vanilla extract and optional chocolate chips, folding them gently into the meringue.

Scoop or pipe the meringue onto the prepared baking sheets, spacing them 1 inch apart.

Bake for about 1 hour until firm to the touch, keeping an eye on the color.

Turn off the oven and let the cookies cool inside with the door slightly ajar for 30 minutes.

Transfer cooled cookies to an airtight container for storage.