Sift powdered sugar, almond meal/flour, and cocoa powder in a large bowl and set aside.
Whip egg whites until foamy and until there is no more liquid remaining in the bottom of the bowl.
Continue whipping the egg whites while slowly incorporating the granulated sugar and cream of tartar to the whites until it makes stiff peaks and are glossy (meringue).
Gently incorporate the sifted mix 1/3 at a time to the meringue mixture until it has the texture of lava and looks like pudding.
Pipe the batter onto any baking sheet/mat into your desired size and shape (traditional macarons are shaped as circles and are about 1 to 4 inches).
Let the piped batter sit until it creates a skin (touch the batter and if it doesn't stick to your finger then they are ready to bake).
Bake for 10-20 mins and check occasionally and gently push the top of the macaron down to see if it's done (if it moves then it's not finished, but if you poke it and it stays still then they are ready).
Take the shells out of the oven and let it cool down (once cooled then you may take off the shells and fill it with any desired filling, I recommend a chocolate ganache).