Measure the egg whites, granulated sugar, powdered sugar, and almond flour into separate small bowls.
Line two large sheet pans with a Silpat mat or parchment paper.
Fit a piping bag with a small, round tip (I like a Wilton #10 or 12).
Heat a small pot of water over medium-low heat.
Place a heatproof bowl over the pot, making sure it doesn’t touch the water.
Add the egg whites and granulated sugar to the bowl. Whisk them together continuously until the sugar has fully dissolved-- about 4-5 minutes.
Transfer the egg whites and sugar to the bowl of a stand mixer fitted with the whisk attachment. Beat the egg whites on medium-high speed (Kitchenaid #6-8) until they form a stiff peak.
Sift the confectioner's sugar and almond flour through a fine-mesh sieve into the egg whites.
Fold in the confectioner's sugar and almond flour gently, making sure not to deflate the egg whites yet. Make sure to scrape all the way to the bottom of the bowl while you fold.
(Optional) Once all of the dry ingredients have been incorporated, remove half of the meringue to a separate bowl and add gel food coloring. To make the teal, I used ¼ teaspoon of Wilton teal gel food coloring.
Smush the batter against the sides of the bowl and fold it back together until the meringue flows smoothly. When the meringue is ready to pipe, you should be able to draw a figure 8 without the stream breaking.
If the batter falls off in clumps or breaks during your figure 8, continue smushing and folding a few more times before testing again.
Transfer the meringue to the piping bag fitted with the round tip.
Pipe 1” macarons about 2” apart on the Silpat-lined baking sheet.
Immediately when you’ve finished piping a tray, hold the tray 6” off the counter and drop it straight down to release any air bubbles. Repeat 5-6 times, or until it appears that any large air bubbles have popped.
(Optional) Make sure to decorate the macarons with sprinkles before they dry.
Allow the macarons to sit at room temperature until they have formed a skin-- about 30 minutes. If it’s a humid day, it may take up to one hour. While the macarons rest, preheat your oven to 325F (see notes).
Bake the macarons one tray at a time for 14 minutes, turning the macarons halfway through baking. Repeat with the second tray.
Allow the macarons to cool fully before removing them from the tray.