Start by prepping your workspace. Use lemon juice or vinegar to thoroughly wipe down a large glass or metal mixing bowl. Pour the egg whites into the bowl, cover, and place in the refrigerator for 24 hours. When ready to use, bring the egg whites to room temperature.

Prepare three large baking sheets by lining them with silicone baking mats or parchment paper and set them aside.

To the egg whites, add the cream of tartar and extract, if using. With a stand mixer or handheld mixer set to medium speed, whisk the mixture until soft peaks begin to form. The initial foam will tighten into bubbles, and soon the beaters will leave faint lines in the mixture. At this point, start adding the superfine sugar, one-third at a time, beating for 5 seconds after each addition. Once all the sugar has been incorporated, increase to medium-high speed and whisk until the mixture forms stiff, glossy peaks. When done correctly, the peaks will be smooth and firm without drooping. You can test this by inverting the bowl; the mixture should stay in place. Gently fold in gel food coloring, if desired.

Sift the almond flour and confectioners’ sugar into a clean mixing bowl, pushing any larger pieces through the sieve with a spoon. Discard as little of the dry mixture as possible to ensure you have the correct quantities.

Slowly fold the whipped egg whites into the dry almond flour mixture in three parts, making sure each addition is fully combined before adding more. As you fold, keep an eye on the batter’s consistency—it should gradually become similar to honey. Perform the figure 8 test by allowing the batter to fall from your spatula in a figure 8 shape; it should take no more than 10 seconds to settle back into the batter. If it takes longer, continue gently folding until you achieve the right texture.

Transfer the macaron batter to a piping bag fitted with a round tip (Wilton 12, Wilton 1A, or Ateco 806 will work well). Holding the piping bag directly over the prepared baking sheets at a 90-degree angle, pipe out rounds about 1.5 to 2 inches in diameter, spacing them 1–2 inches apart. Tap the baking sheets on the counter to release any air bubbles and use a toothpick to pop any visible ones.

Let the piped macarons rest at room temperature for 30–60 minutes until the tops are dry to the touch and no longer tacky. This will help them form their characteristic ruffled "feet" when baked. Avoid leaving them out for too long, as they may begin to deflate.

Bake the macarons for about 13 minutes, checking their doneness by gently touching the tops. If they wobble, bake for an additional 1–2 minutes. Once firm and no longer moving, remove them from the oven and let them cool on the baking sheets for 15 minutes before transferring to a wire rack. If the macarons stick to the parchment paper, allow them to cool for a bit longer.

Once completely cooled, they are ready to be filled. Use a piping bag or a knife to add your chosen filling, then sandwich the macarons together. You can enjoy them immediately, but some bakers recommend refrigerating the assembled macarons for 12–24 hours to allow the flavors to develop. Bring them back to room temperature before serving.

Store any leftovers in the refrigerator for up to five days.