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

In a clean mixing bowl, beat the room temperature egg whites on medium speed until foamy, about 2-3 minutes.

Gradually add a pinch of salt, then the granulated sugar, one tablespoon at a time, beating until stiff peaks form, around 5-6 minutes.

Sift the unsweetened cocoa powder into the meringue and gently fold until combined.

Add vanilla extract and fold in chocolate chips or chunks, if using.

Pipe the meringue onto the prepared baking sheets, spacing them about 1 inch apart.

Bake for approximately 1 hour, or until the cookies feel dry.

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

Transfer the cooled cookies to an airtight container for storage.