Line two baking sheets with parchment paper. Set aside.
Place a fine-mesh sieve over a medium-sized bowl. Add the confectioner's sugar and almond flour to the sieve and sift them together. Discard any large lumps that remain in the sifter. Set aside.
Fill a small saucepan halfway with water. Place it over high heat and bring to a rolling boil.
Add the egg whites and granulated sugar to the bowl of a stand mixer.
Remove the saucepan from the heat and place the bowl with the egg whites on top. Begin whisking the egg whites and sugar together until the sugar has fully dissolved— about 2 minutes.
Remove the bowl from the heat and place it on the mixer. Beat the egg whites on medium speed until they hold a stiff peak— about 8-10 minutes with a stand mixer on speed 6-8.
Once the egg whites can hold a stiff peak, remove the bowl from the mixer stand and place the fine-mesh sieve on top. Pour the confectioner's sugar/almond four mixture into the sieve and sift it into the egg whites. Again, discard any remaining clumps.
Begin to gently fold the dry ingredients into the egg whites. The proper folding technique is to cut through the center of the batter with your spatula and scoop around the bottom of the bowl and flip the batter from the bottom to the top. Turn the bowl 90 degrees and repeat.
Once the dry ingredients have been fully incorporated, it’s time for the Macaronage stage. Smush all of the batter against the sides of the bowl and then scrape it down and fold it back together again. Repeat 5-6 times, or until the batter reaches the “lava stage”. You should be able to lift the batter with your spatula and draw a figure 8 without the batter clumping. If it doesn’t flow evenly and smoothly, repeat the smushing another 1-2 times and test again.
Transfer the batter to a piping bag and pipe 1” circles that are about 2” apart on the baking sheet. Once you’ve finished the first tray, pick it up approximately 6” off the counter, and drop it straight down to release any air bubbles. Repeat 6-7 more times, or until you do not see any large air bubbles remaining.
Continue piping the second tray and then drop it to release any air bubbles - as you did the first tray.
Allow the macarons to rest at room temperature for at least 30 minutes (up to an hour if it’s humid) or until they have developed a skin. You should be able to touch the top of the macaron without it sticking to your finger.
While the macarons are resting, preheat the oven to 325F.
Bake the macarons in a preheated oven one tray at a time— on the center rack— for 12-14 minutes, or until the bottoms are just starting to turn a light brown.
Remove and leave the macarons on the tray to cool.