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

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

Add a pinch of salt and gradually incorporate the sugar one tablespoon at a time, beating for 5-7 minutes until stiff, glossy peaks form.

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

Add the vanilla extract and fold gently. If using, fold in chocolate chips or chunks.

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

Bake in the preheated oven for approximately 1 hour, or until dry to the touch and easily lifted from the parchment.

After baking, turn off the oven and leave the cookies inside with the door slightly open to cool for about 30 minutes.