Preheat oven to 350 degrees F (175 degrees C). Line cookie sheets with parchment paper.

Beat egg whites and salt in a large glass or metal bowl until foamy. Gradually add sugar, beating continuously until stiff, glossy peaks form. Fold in vanilla extract, chocolate chips, and peanuts, if using.

Drop rounded spoonfuls of the mixture onto the prepared baking sheets, spacing them about 1 inch apart.

Place the cookies into the preheated oven. Immediately turn the oven off and leave the door closed. Let cookies stand in the turned-off oven for 5 to 6 hours or overnight, until dry and crisp.

Remove cookies from the oven and store in an airtight container.