Prepare 2 baking sheets with silicone mats, teflon, or templates and parchment paper. Fit a piping bag with a round piping tip. Set aside. Preheat oven to 285°F.
Pulse the almond flour, powdered sugar, and matcha powder in a food processor and sift into a bowl. Discard any large chunks. Whisk the dry ingredients and set aside.
In a clean stand mixer bowl, add egg whites, sugar, and egg white powder (if using). Whisk to combine and place bowl over a double boiler. Heat, whisking regularly, until the sugar dissolves, about 90 seconds. Remove the bowl from the double boiler and carefully dry off the bottom.
Place the bowl in the stand mixer and whisk on a medium speed (KitchenAid 4) until you almost have stiff peaks, 7- 10 minutes. Add your gel color. Beat until you have stiff peaks, another 3- 5 minutes.
Add the dry ingredients to the meringue and begin folding the ingredients together. Once everything is combined, continue folding until the batter flows slowly like lava.
Pipe macaron shells onto prepared baking sheets. Let the macarons dry until you can lightly brush the tops with your finger (15 mins for me). Bake for 20- 22 minutes, rotating the baking sheet halfway through. Gently poke a shell, if it is firm, remove the tray from the oven to cool. If they wiggle, add another minute or two.
Let the macaron shells cool on the sheet for 10 minutes before transferring them to a cooling rack.