Wipe down a large glass or metal mixing bowl with lemon juice or vinegar. Add egg whites. Cover and refrigerate for 24 hours, then bring to room temperature.

Line 3 large baking sheets with silicone baking mats or parchment paper. Set aside.

Add cream of tartar and extract (if using) to egg whites. Using a handheld mixer or stand mixer fitted with a whisk attachment, beat together on medium speed until very soft peaks form.

Add about ⅓ of the superfine sugar. Beat on medium-high speed for 5 seconds, then with the mixer continuing to run, add another ⅓ of the sugar. Beat for 5 seconds, then with the mixer continuing to run, add the remaining sugar. Beat on medium-high speed until stiff glossy peaks form.

Using a rubber spatula, slowly and gently fold the food coloring (if using) into the egg whites.

Sift the almond flour and confectioners’ sugar together in a large glass or metal mixing bowl.

Slowly fold the beaten egg whites into the almond flour mixture in 3 separate additions, folding until combined before adding the next addition.

Continue folding the batter until it thins out into the consistency of honey. Perform the figure 8 test.

Spoon the macaron batter into a piping bag fitted with a medium round piping tip.

Holding the piping bag at a 90 degree angle over the baking sheet, pipe batter in 1.5 – 2 inch rounds about 1-2 inches apart on prepared baking sheets.

Let the piped macarons sit out until they are dry and no longer tacky on top, usually 30-60 minutes.

Preheat the oven to 325°F (163°C).

Bake for 13 minutes. Test for doneness by lightly touching the top of a macaron.

Let the shells cool on the baking sheet for 15 minutes, then transfer to a cooling rack to continue cooling.

After cooling, the shells are ready to fill and sandwich together.

You can eat right away or refrigerate them 12-24 hours to mature the flavors.