Set the oven rack to the lower third position. This is just below the center of the oven. Line 3-4 more baking sheets with parchement paper (or silicone mats if that is preferred). Preheat the oven to 325°F (if your oven runs hot set to 300℉).
Mix together the almond flour and confectioners sugar with a whisk until combined. Using a fine-mesh sifter, sift the almond flour and confectioners sugar into a large bowl. Repeat a second time and discard any clumps each time. Do not force the clumps through the sifter.
Combine egg whites and granulated sugar into the bowl of a stand mixer. Boil 1-2 inches of water and reduce to a simmer. set bowl with combined egg whites and granulated sugar over boiling water, being sure not to touch the bowl to the water. Using a whisk continuously whisk the sugar and egg whites until the sugar is dissolved. Use your finger to reach in and feel if the sugar is dissolved. If it is still gritty it needs a little more time. Be careful not to cook the egg whites.
Once disolves. attache the boal to the mixer, fitted with the whisk attachment, whip the egg whites on high until soft peaks form. Add the meringue powder and whip a bit longer, once stiff peaks have formed add the vanilla and gel food coloring of your choice.
Continue to whip on high speed until a thick, glossy meringue forms. The meringue should be stiff enough to stay inside the bottom half of the whisk and forming a stiff enough peak that will stay peaked off the end of the whisk once tilted back. Take extra care not to over whip.
Using a silicone spatula, fold the meringue into the almond mixture until fully combined. Scrap the sides of the bowl and drag through the middle creating a figure 8.
Over-mixing or under-mixing will cause issues with how the macarons bake up. After a couple of stirs, you'll need to stop and check the consistency of the batter. Continue to do this until the batter is just right. The batter should be shiny and flow like lava. Slow and smooth without breaking. The batter should slide off the spatula as you draw a figure 8 without the batter breaking.
Transfer the batter to a large pastry bag fitted with a medium round piping tip. You will likely need two of these prepared, as the batter will overfill one large piping bag.
Pipe 1 to 2 inch rounds onto the prepared baking sheets. Be sure to pipe straight up and down, like a dollop. I like to count.. 1,2,3,4 stop to create consistency in size.
Once piped, drop the baking sheet flat on the countertop from a couple inches above the countertop to bring any air bubbles to the surface. Do this several times until most bubbles are popped. Use a toothpick to pop and smooth and stubborn bubbles. If you are using sprinkles, now is the time to lightly sprinkle the shells, after popping the air bubbles, while the macarons are setting.
Let the macarons sit for 50-60 minutes, until a dry skin forms on the surface. You should be able to gently run your fingers across the top of the macaroon without it sticking before it is ready to go into the oven.
Bake one sheet at a time for 12-15 minutes (your oven may vary so watch with the light on but try not to open the oven too much). The macaroons are done when you can gently press on the shell and lightly rock your finger back and forth without it moving. If the shell if wiggly, then it needs another minute or two.
