Pre-heat oven to 325°F.
Separate the eggs from the egg whites (if using fresh eggs). Measure out 100 g (about 3 large eggs).
Dry Ingredients: In a separate bowl, sift the icing sugar, almond flour, and cocoa powder together. Repeat the sifting process to ensure there are no clumps. If there are any clumps, discard them.
Prepare the Meringue: In a stand mixer fitted with the whisk attachment (or bowl if using a hand mixer), add the egg whites and a pinch cream of tartar. Beat on high until foamy.
Once the egg whites are foamy, turn the mixer down to the lowest setting possible, and slowly add in the granulated sugar. Be sure to incorporate all the sugar into the egg whites.
Turn up the mixer again on high, and keep beating egg whites until stiff peaks form. DO NOT OVER BEAT.
Macronage: With a rubber spatula, fold the dry mixture into the egg whites, until the paste flows like a ribbon/lava.
Fit a pastry bag with a #12 round tip, if using, and trim the bottom as appropriate.
Pipe circles onto the prepared baking sheet. You should get about 50 circles in total depending on the size of your macarons.
Once piped, rap the sheet on the counter to release all the air bubbles.
Rest for 30 minutes, until the shells have formed a skin, and are no longer tacky to touch.
Bake Shells: Bake in the oven, at 300ºF-325°F for 12-13 minutes.
Check for doneness, by wiggling the shell. Shells are done when they don't move from the feet. If it wiggles from the feet, then bake for another minute, and check again.
Cool the shells in the tray.