Line a sheet pan with parchment paper. Make sure the paper lays flat or your macarons won’t be perfect circles.
Sift together the powdered sugar and almond flour. Discard any large lumps that remain in the sifter. If you don’t have a sifter, you can pulse them in the food processor for 10-15 seconds.
In the bowl of a stand mixer, beat the egg white on medium-low speed until it becomes foamy and white. Add the cream of tartar.
With the mixer on medium-high, slowly add in the granulated sugar. I like to add about one tablespoon every 5 seconds. Whip the egg white on medium-high speed until it forms stiff peaks.
Add half of the dry mixture to the egg white and fold it gently until the dry mixture is incorporated. Add the remaining half of the dry mixture and continue to gently fold until the batter is uniform and no more lumps remain. This should take about 15-20 folds per addition.
This part is counterintuitive, but trust me… you have to deflate the egg whites until you get the batter to the “lava stage”. Smush the batter along the sides of the bowl in a circular motion and then scrape the sides of the bowl and fold the batter back together.
Once the batter reaches the “lava stage” you should be able to draw an 8 with the batter and it should reincorporate within 10-15 seconds. If the batter doesn’t reincorporate, give it a few more folds and try the figure 8 again.
Transfer the meringue to a piping bag fitted with a round tip (I like Wilton #12). If you don’t have a piping bag, you can also use a large ziploc bag with the end cut off.
Pipe 1” circles on the parchment lined baking sheet. Make sure to pipe them at least 2 inches apart.
Immediately after piping, hold the tray approximately 6 inches off the counter and drop it straight down onto the counter. Repeat 10 times.
Preheat the oven to 300°F.
Let the macarons sit at room temperature for at least 20 minutes, or until they develop a skin. After 20 minutes, you should be able to touch the macarons without them sticking your finger. If they are still sticky, let them sit another 20 minutes.
Bake the macarons on the middle shelf for 18-20 minutes. The macarons should be set all the way through but not browned on top. If your oven doesn't cook evenly, make sure to turn the pan 180° half way through baking.
Remove the macarons from the oven and let them cool on the tray.