Place the macaron tart template and a silicone mat on top of an upside down baking sheet.
Place a medium sized round piping tip (like a Wilton 2A) in a large piping bag. Twist the bag right behind the tip and add a clip to seal off the opening. Place the bag tip down into either a clean tall cup with the edges folded over the rim to keep the bag open, or clip it into a bag holder.
Using a kitchen scale, carefully weigh out and sift the confectioner’s sugar and almond flour into a medium mixing bowl. Whisk well to fully blend the two together.
Place egg whites, granulated sugar, and cream of tartar into a large mixing bowl, and begin beating with a whisk attachment using either a handheld mixer or a stand mixer for 3 minutes on a medium low speed (Kitchen Aid Speed 4).
Turn up the mixer to a medium speed (Kitchen Aid Speed 6) and beat for an additional 3 minutes.
Add the gel food coloring drops.
Turn mixer up to medium high speed (Kitchen Aid Speed 8) and beat for 3 more minutes, or until peaks are very stiff and the meringue clumps up in the center of the whisk. Test stiffness by removing whisk and pointing it upward. (See photos in Basic French Macarons post) Once the peaks can firmly hold their shape when flipped upright, your meringue is ready.
Pour half of your almond flour/confectioner’s sugar mixture into the bowl with your meringue, and fold 15 times. One fold is scraping all the way around the edge of your batter in your bowl, and then dragging your spatula through the middle. Be sure to scoop around the bottom of the bowl as well so you don’t miss any dry ingredients.
Pour in the remaining powdered sugar and almond flour, and continue folding (approximately 30 more folds) until dry ingredients are fully incorporated, your batter is no longer super clumpy. Do not overfold. Please note this recipe stays a bit thicker than most, and should not be folded to the traditional figure 8 test consistency. Start checking your batter’s readiness every 5 folds or so at this point by scraping all batter down to the bottom of your bowl, and then wiggling your bowl back and forth several times. If the batter levels out with few peaks and lines remaining (but not completely smooth/flat), it should be ready. (See photos in Basic French Macarons post for reference.)
Pour batter into prepared piping bag, and twist the opening off. Hold your bag at the twist between your thumb and pointer finger. Remove the clip.
Holding the piping bag straight up and down, apply pressure to begin piping your batter in the center of each circle edge of your first macaron tart template. Apply pressure until the batter reaches the edges of the scallop shape, and then pull the batter towards the center. Repeat the process all the way around the edge, and then continue the same motion just inside of the first row, repeating until you've filled the entire template. (See photos and videos for reference)
Once you’ve piped the base for your tart, firmly bang the tray on the counter a few times to pop any air bubbles and smooth out shells. Pop any remaining large bubbles with a toothpick. Remove the template from under the silicone mat and place in between the second prepared tray/silicone mat.
For the top part of the macaron tart, pipe in the center of each circle until the batter reaches the edges, and then releasing pressure using a small quick circular flick to release your tip from the piped macaron. For the top you'll only want to pipe a "frame" of circles and will not continue filling in the center of the shape.
Repeat the tray banging/popping holes step for the frame/rim.
Begin preheating your oven to 300 degrees, using an oven thermometer ensure accurate temperature readings.
Set aside shells to dry until they form a skin and are no longer tacky to the touch. Once you can gently run a finger over your shells, they are ready to bake. Use a fan to speed up the process, rotating the tray every few minutes to ensure even drying. This usually takes at least 16-20 minutes for me even with a fan. (To skip this resting step, follow steps in my post "How to Oven Dry Macarons and Skip the Resting Process)
Once the macaron shell crusts are dry, and the oven has fully preheated to 300, place one tray in the center of the middle rack of the oven. Bake for 18 minutes.
Quickly open door to check the shell’s doneness by gently wiggling the top of the shell to see if it’s firm. If it moves at all, rotate the tray and bake for another 2 minutes.
Check macaron shell crusts by performing the same test, gentling wiggling the tops or pressing on the sides just above the feet. If they are still unstable, bake for one more minute, and check again. Repeat until the macarons are firm and do not budge.
Repeat the bake with the second tray.
Allow the macarons to cool completely, and the carefully remove from silicone mat by supporting it with your hand, flipping it over quickly with the mat, and then gently peeling the mat off the shells.