In a medium bowl, sift together almond flour and powdered sugar, discarding any almond pieces that do not pass through the sifter. Repeat. Set sifted ingredients aside.
In a large clean mixing bowl with the mixer’s whisk attachment, beat egg whites on medium speed until foamy. Beat in the cream of tartar. Add the granulated sugar 1 tablespoon at a time while continuing to beat. Then increase the speed to medium-high and beat until stiff peaks form. To check for stiff peaks, detach the whisk and turn it upside down. The peak is stiff if it stands straight up without collapsing.
Add lemon essential oil, lemon juice, and pink gel food coloring. Beat on medium speed for one more minute until pink.
Add 1/2 of the sifted almond flour/sugar mixture to the whipped egg whites and mix until mostly incorporated. Then add the remaining almond flour mixture. Gently fold the mixture, running the spatula clockwise up around the sides. Do not overmix. Test whether the batter is ready by picking up a dollop of batter on the spatula and dropping it back into the bowl. The dropped batter should take 30 seconds to flatten back into the bowl batter. If not, fold again, test, and repeat. Once your test dollop smooths out in 30 seconds, STOP folding. If overfolded, the mixture will be runny and will make hard, flat cookies.
Transfer the batter into a pastry bag with a large round tip or into a gallon zipper bag with the corner cut off. Pipe 1.5-inch hearts onto the macaron mat in the indentations provided. Fill the entire heart. If needed, use a toothpick to spread the batter to completely fill the hearts.
Tap the baking sheets firmly on the counter a few times to remove any air bubbles. Let the macarons dry out for 30-45 minutes to form a skin on top. Test by touching. If no batter sticks to your finger, they are ready. If not, let them sit a little longer and test again.
Preheat the oven to 300°F. Bake the macarons for 12-15 minutes on the middle rack, rotating the cooking sheet after half the cooking time. Keep an eye on them and do not let them brown, or they will lose their pink color and overcook. They are done if they feel hard, and you can detach one easily from the mat.
Cool completely. Then carefully remove cookies from the mat by pulling the mat away from the cookie.