Preheat the oven to 300°F (150°C). Line 2 baking sheets with parchment paper, or teflon sheet, or silicone mat.
To prepare dry ingredients, sift together almond flour, powdered sugar and cocoa powder twice. Note: If you have up to 2 tablespoons of chunky dry ingredients left in the sifter, you don't have to replace it. Simply discard those chunky bits.
To make meringue, in a clean mixing bowl with a whisk attachment, combine egg whites, granulated sugar, cream of tartar and salt and beat the mixture on medium speed until soft peaks form. (I set it to speed 4 on my KitchenAid stand mixer. It takes 30-40 minutes to whip the meringue, but it's well worth it for nice and full shells.)
When the meringue reaches soft peaks stage, add red gel food coloring and vanilla extract.
Continue beating the egg whites on the same medium low speed until hard peaks form. Visual cues: Meringue should ball up inside the whisk, and when you lift the whisk, the meringue should hold a pointy end and have sharp ribs.
To make batter, sift almond flour mixture into the meringue. Using a silicone spatula, fold the dry ingredients into the meringue until fully incorporated. Then continue to fold the batter until it’s runny enough to draw a figure eight. To test, take a small amount of batter and drop it into the bowl. If the small peaks dissolve into the batter on its own in about 10 seconds, the batter is ready. If not, fold couple more times and test again. Be careful not to over-fold the batter. (TIP: Making french macarons is all about the technique. This is one of the most crucial step. Let me try to describe the folding motion as best as I can: run the spatula clockwise from the bottom, up around the sides and cut the batter in half. If you’re beginner macaron-baker, I suggest to count every fold. It takes roughly about 50 folds to reach the proper consistency. After 50 folds, start testing the batter, and continue testing after every couple folds.)
To pipe macaron shells, transfer the batter into a pastry bag, fitted with a round tip. (I used this Wilton 12 tip.) Hold the pastry bag at straight 90° angle and pipe about 1.5-inch rounds about an inch apart on prepared baking sheets. (TIP 2: Download my free macaron template. Simply pipe the batter to fill inner circle.) Tap the baking sheets firmly on the counter (or using your hand) a few times to get rid of any air bubbles. You can also use a toothpick to burst some large air bubbles. This step ensures smooth tops.
Let the macarons rest on the counter for 15 minutes before baking.
To bake, working one baking sheet at a time, place one tray with macarons on the middle rack. (TIP: To prevent browning, place an empty baking sheet on top rack to shield the heat.) Bake for about 15-18 minutes. It’ll take longer for larger macarons. To test for doneness, touch a macaron lightly and try to move it. If it slides and wobbles, bake a minute or so longer. The cooked macarons should be firm to touch and the base shouldn’t move. (TIP: It’s always better to slightly over-bake macarons than under-bake them!)
Cool macarons complete and then remove the shells from the parchment paper. (TIP: Don't remove the shells while warm, you may risk breaking the shells, or the bottom might get stuck to the baking surface.)