Line cookie sheet with parchment paper or brown paper bag
Beat egg whites until foamy
Add in cream of tartar and beat until soft peaks form.
Slowly add in granulated sugar and beat until stiff peaks form.
Mix together cocoa powder and powdered sugar. Sift or whisk so there are no lumps.
Fold in mixture to egg whites. Fold gently, do not stir.
Place meringue in a piping bag with a large star tip and pipe onto prepared baking sheet. Or use a spoon and scoop onto baking sheet in mounds.
Optional: Add some mini chocolate chips to the top of the cookies before baking.
Bake for 1 hour and then turn off oven and leave in oven overnight or at least two hours until oven is completely cooled.
Notes
Egg Whites: Make sure that none of the yolk gets into the egg white while separating your eggs. Your meringue will not whip properly if it does. Room temperature eggs whip better than cold eggs.
Clean your bowl and beater first. Be sure there is no dirt, oily residue etc in your bowl or on your beater. Any bit of fat can prevent your egg whites from forming properly.
Folding. When adding in your powdered sugar/cocoa mixture be sure and do so gently. Fold it, don't stir it as you don't want to deflate your egg whites.