Using a fine-mesh strainer, sift both your almond flour and confectioners' sugar into a glass bowl. Set aside.
Prepare your meringue. Begin by whipping your egg whites on low speed until they are frothy. Add your cream of tartar. Increase the speed to medium and continue whipping. When the whisk is leaving lines in the egg whites and the meringue begins to look soft and pillowy, slowly pour the granulated sugar into the mixture.
Add your vanilla extract. If you're adding gel color to your shells, add it to the meringue at this point as well.
Increase the speed to high. Continue whipping until your meringue is creamy and glossy and has stiff peaks and clumps inside the whisk.
Gradually add your sifted dry ingredients to the meringue. Using a flexible silicone spatula, incorporate the almond flour and confectioners' sugar into the meringue with a folding motion. Press the spatula against the side of the bowl to release any air bubbles and achieve the proper consistency.
The consistency of the batter should not be too runny or too stiff. Check the batter often by picking up the spatula and letting the batter run off. If the batter falls into the bowl in a ribbon-like way, disappearing back into the batter, you're done mixing.
Prepare your baking sheets. If using silicone mats, place them on the baking sheets. If using parchment paper, put a bit of macaron batter in the four corners of each baking sheet to help adhere the parchment to the sheets.
Transfer the batter to a pastry bag with a pastry tip. Pipe the macarons onto the baking sheet so that they are 1 1/2 inches wide and 3/4 inch apart. Once you are done piping, tap the baking sheet against the counter a few times to dislodge any air bubbles in the batter.
Allow the shells to dry. This should take 30 minutes to 1 hour. Your macarons are dry when they're no longer sticky to the touch and have developed a skin.
Preheat your oven to 300 degrees. Use an oven thermometer if your oven is unpredictable. When the macaron shells are dry, bake them for 12-18 minutes. It's difficult to give an exact baking time for macarons, since every oven is different.
Keep a close eye on your macarons as they bake. If you touch them and they wobble, they may need a little more time in the oven.
Remove the shells from the oven and let them cool on the pan. The shells should pop off the sheet with ease once they are cool.
Pipe a filling onto half of the macaron shells, and gently sandwich the shells together. Enjoy!
A basic macaron recipe serves as good base for experimenting with different flavorings and colorings. This recipe can be tweaked to produce many different flavors. Macarons can be filled with buttercream, ganache, or jam.