Preheat oven to 250 degrees F. Line cookie sheets with parchment paper or use the Silicone Baking Mats to prevent the cookies from sticking.
In a small bowl, combine the 1/4 cup cocoa and sugar together; set aside.
In a large bowl using your electric mixer, beat egg whites until foamy/frothy. Check out How To Make A Perfect Meringue. While beating to the frothy stage, add salt, cream of tartar, and vanilla extract. After reaching the frothy stage, add the cocoa/sugar mixture (1 tablespoons at a time) while continuing beating until the egg whites are stiff and glossy.
Drop batter by tablespoonfuls onto prepared baking sheets (1-inch apart).
In a small bowl, combine the remaining 1 teaspoon cocoa and cinnamon. Using a sieve or a sifter, sprinkle mixture over the non-baked cookies.
Bake 90 minutes; turn off the oven, open the door slightly (secure with a wooden spoon), and allow cookies to cool in the oven. Remove from oven and store in a tightly covered (airtight) container.
Chocolate Meringue Cookie Recipe: https://whatscookingamerica.net/Cookie/ChocolateMeringue.htm