Line a baking sheet with silicon mat.
Sift the almond flour and powdered sugar through a fine sieve, discarding any remaining coarse almond flour.
In a separate bowl, beat the egg whites with cream of tartar until they become frothy. Gradually add the caster sugar in three parts, continuing to beat until stiff peaks form.
Add your preferred gel food color and mix until the color is evenly incorporated.
Fold the sifted almond flour mixture into the egg white mixture in two parts, using a spatula. Continue the folding motion, gently turning the batter until it reaches a smooth consistency and drops off the spatula in a thin, flat ribbon.
Transfer the batter into a pastry bag equipped with a ¼ inch round tip. Pipe the batter into evenly sized macarons, aiming for 24 per pan.
Tap the baking sheet 3-4 times to eliminate any potential air bubbles. Utilize a toothpick to disperse any remaining bubbles.
Allow the macarons to rest at room temperature for 30-60 minutes, or until the tops are no longer sticky to the touch. Meanwhile, preheat the oven to 300°F (148°C).
Bake the macarons for 15-17 minutes, then let them cool on the baking sheet before transferring them to a wire rack to cool completely before filling.