Flip two baking sheets upside down and line them with silicone baking mats (my preferred method) or parchment paper. Set aside.
In a large bowl, sift together the powdered sugar and almond meal.
In the bowl of a stand mixer, whisk the egg whites and cream of tartar on medium-low speed until foamy. Slowly sprinkle in the sugar and add the food coloring. Increase the speed to medium-high and continue whisking until stiff peaks form.
Use a rubber spatula to gently fold the almond meal/powdered sugar into the stiff egg whites. Scrape the batter against the sides and bottom of the bowl. The batter is ready when it looks glossy and flows in slow ribbons off the spatula. You can also try to draw a figure 8 with the batter. After 30 seconds, look for the 8 to have soft edges to know it's ready.
Fill a piping bag fitted with a small round piping tip. Pipe the batter into 1 ½-inch rounds spaced 2 inches apart. Tap the baking sheets on the counter to release any air bubbles. You can pop them with a toothpick.
Let the macarons sit at room temperature until the shells feel dry, about 30-60 minutes.
While the macarons are resting, preheat your oven to 300F/149C. This temperature could range from 275 F-325 F, I recommend testing a few and seeing what works best for your oven!
Bake each tray separately for about 13-14 minutes. Touch the top of the shell. If it moves, give it 2 more minutes. The top shouldn't budge from the food when they are done baking. Remove the tray from the oven and let it cool completely on a wire cooling rack before filling.